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EXCHANGE ONLINE LIMITS

 * Article
 * 01/26/2023
 * 46 minutes to read
 * 23 contributors

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IN THIS ARTICLE

Find the Exchange Online limits for a variety of service areas, including
address book limits, mailbox storage limits, and reporting and message trace
limits, to name just a few.

Note

If you need assistance with a task or if you are troubleshooting a problem, you
might find the following articles helpful:

 * Email (for help creating and sending email)
 * Email in Microsoft 365 for business - Admin Help
 * Fix Outlook and Microsoft 365 problems with Microsoft Support and Recovery
   Assistant
 * Email non-delivery reports
 * Exchange Online Help

The limits in Microsoft Exchange Online fit into one of the following
categories:

 * Address book limits

 * Capacity alerts

 * Distribution group limits

 * Exchange ActiveSync limits

 * Hold limits

 * Journal, transport, and inbox rule limits

 * Mailbox folder limits

 * Mailbox storage limits

 * Message limits

 * Moderation limits

 * Receiving and sending limits

 * Reporting and message trace limits

 * Retention limits

Important

 * The limits applied to a Microsoft 365 organization may differ depending on
   how long the organization has been enrolled in the service.
 * When a limit is changed in the Microsoft data centers, it can take some time
   to apply the change to all existing customers.
 * You can't modify most of these limits, but you and your users should be aware
   of them.
 * These limits apply to both internal and external recipients.
 * By default, Exchange Online Protection (EOP) protects Exchange Online
   mailboxes. For limits that apply to EOP features in Exchange Online, see
   Exchange Online Protection limits.
 * For information about Office 365 group limits, see "How do I manage my
   groups?" in Learn about Microsoft 365 groups.


ADDRESS BOOK LIMITS

 * Address list limit: The maximum number of address lists that can be created
   in an Exchange Online or Exchange Server organization. This number includes
   the default address lists in Exchange Online, such as All Contacts and All
   Groups.
   
   Note
   
   A maximum of 20 address lists can be assigned to a single offline address
   book (OAB). The maximum size of a single offline address book is 1GB.

 * Offline address book limit: The maximum number of offline address books (OAB)
   that can be created in an Exchange Online or Exchange Server organization.

 * Address book policies limit: The maximum number of address book policies
   (ABP) that be created in an Exchange Online or Exchange Server organization.

 * Global address lists: The maximum number of global address lists (GAL) that
   be created in an Exchange Online or Exchange Server organization.


ADDRESS BOOK LIMITS

Feature Microsoft 365 Business Basic and Standard Microsoft 365 Business Premium
Microsoft 365 E3/E5 Office 365 Enterprise E1 Office 365 Enterprise E3/E5 Office
365 Enterprise F3 Address list limit 1000 1000 1000 1000 1000 1000 Offline
address book (OAB) limit 250 250 250 250 250 250 Address book policies (ABP)
limit 250 250 250 250 250 250 Global address lists limit 250 250 250 250 250 250


ADDRESS BOOK LIMITS ACROSS STANDALONE PLANS

Feature Exchange Server Exchange Online Plan 1 Exchange Online Plan 2 Exchange
Online Kiosk Address list limit unlimited 1000 1000 1000 Offline address book
(OAB) limit 250 250 250 250 Address book policies (ABP) limit 250 250 250 250
Global address lists limit 250 250 250 250


CAPACITY ALERTS

Exchange Online provides three kinds of notifications when a user's mailbox is
nearing, or at, capacity:

 * Warning: The user receives an email warning that the mailbox is approaching
   the maximum size limit. This warning is intended to encourage users to delete
   unwanted mail.

 * Prohibit Send: The user receives a prohibit-send notification email when the
   mailbox size limit is reached. The user can't send new messages until enough
   email is deleted to bring the mailbox below the size limit.

 * Prohibit Send/Receive: Exchange Online rejects any incoming mail when the
   mailbox size limit is reached, and sends a non-delivery report (NDR) to the
   sender. The sender has the option to try resending the mail later. To receive
   messages again, the user must delete email until the mailbox is below the
   size limit.


CAPACITY ALERTS

Feature Microsoft 365 Business Basic and Standard Microsoft 365 Business Premium
Microsoft 365 Enterprise E3/E5 Office 365 Enterprise E1 Office 365 Enterprise
E3/E5 Office 365 Enterprise F3 Warning 49 GB 49 GB 98 GB 49 GB 98 GB 1.96 GB
Prohibit Send 49.5 GB 49.5 GB 99 GB 49.5 GB 99 GB 1.98 GB Prohibit Send/Receive
50 GB 50 GB 100 GB 50 GB 100 GB 2 GB


CAPACITY ALERTS ACROSS STANDALONE PLANS

Feature Exchange Server Exchange Online Plan 1 Exchange Online Plan 2 Exchange
Online Kiosk Warning 1.9 GB1 49 GB 98 GB 1.96 GB Prohibit Send 2 GB1 49.5 GB 99
GB 1.98 GB Prohibit Send/Receive 2.3 GB1 50 GB 100 GB 2 GB

1 This is the default value for Exchange Server organizations. Administrators
can change this value for their organization.


DISTRIBUTION GROUP LIMITS

These limits apply to distribution groups in your organization's shared address
book.

 * Maximum number of distribution group members: The total recipient count is
   determined after distribution group expansion.

 * Limit sending messages to large distribution groups: Distribution groups that
   contain the number of members specified by this limit must have delivery
   management or message approval options configured. Delivery management
   specifies a list of senders who are allowed to send messages to the
   distribution group. Message approval specifies one or more moderators who
   must approve all messages sent to the distribution group.

 * Maximum message size for large distribution groups: If a message is sent to
   5,000 or more recipients, the message size can't exceed this limit. If the
   message size exceeds the limit, the message isn't delivered, and the sender
   receives a non-delivery report (NDR).


DISTRIBUTION GROUP LIMITS

Feature Microsoft 365 Business Basic and Standard Microsoft 365 Business Premium
Microsoft 365 Enterprise E3/E5 Office 365 Enterprise E1 Office 365 Enterprise
E3/E5 Office 365 Enterprise F3 Maximum number of distribution group members1
100,000 members 100,000 members 100,000 members 100,000 members 100,000 members
100,000 members Limit sending messages to large distribution group 5,000 or more
members 5,000 or more members 5,000 or more members 5,000 or more members 5,000
or more members 5,000 or more members Maximum message size for distribution
groups with 5,000 to 99,999 members 25 MB 25 MB 25 MB 25 MB 25 MB 25 MB Maximum
message size for distribution groups* with 100,000 members 5 MB 5 MB 5 MB 5 MB 5
MB 5 MB Maximum number of distribution group owners 10 10 10 10 10 10 Maximum
number of groups a user can create 300,0002 300,0002 300,0002 300,0002 300,0002
300,0002

* Includes dynamic distribution groups.
1 If you are using Azure Active Directory DirSync, the maximum number of
distribution group members that you can synchronize from your on-premises Active
Directory to Azure Active Directory is 15,000. If you are using Azure AD
Connect, that number is 250,000, but the supported limit of distribution group
members is still 100,000.
2 This limit also applies to admins.


DISTRIBUTION GROUP LIMITS ACROSS STANDALONE OPTIONS

Feature Exchange Server Exchange Online Plan 1 Exchange Online Plan 2 Exchange
Online Kiosk Maximum number of distribution group members 100,000 members1
100,000 members 100,000 members 100,000 members Limit sending messages to large
distribution group 5,000 or more members1 5,000 or more members 5,000 or more
members 5,000 or more members Maximum number of distribution group owners 10 10
10 10 Maximum number of groups a user can create 2502 2502 2502 2502

1 This is the default limit for Exchange Server organizations. Administrators
can change this value for their organization.
2 This limit also applies to admins.


EXCHANGE ACTIVESYNC LIMITS

The following limits apply to Microsoft Exchange ActiveSync, a client protocol
that synchronizes mailbox data between mobile devices and Exchange.

 * Exchange ActiveSync device limit: The maximum number of Exchange ActiveSync
   devices per mailbox.

 * Exchange ActiveSync device deletion limit: The maximum number of Exchange
   ActiveSync devices that an Exchange administrator can delete in a single
   month.


EXCHANGE ACTIVESYNC LIMITS

Feature Microsoft 365 Business Basic and Standard Microsoft 365 Business Premium
Microsoft 365 Enterprise E3/E5 Office 365 Enterprise E1 Office 365 Enterprise
E3/E5 Office 365 Enterprise F3 Exchange ActiveSync device limit 100 100 100 100
100 100 Exchange ActiveSync device deletion limit 20 20 20 20 20 20


EXCHANGE ACTIVESYNC LIMITS ACROSS STANDALONE OPTIONS

Feature Exchange Server Exchange Online Plan 1 Exchange Online Plan 2 Exchange
Online Kiosk Exchange ActiveSync device limit 100 100 100 100 Exchange
ActiveSync device deletion limit 20 20 20 20


HOLD LIMITS

Holds include Microsoft 365 retention policies and retention label policies,
Microsoft Purview eDiscovery case holds, and In-Place Holds. These count towards
the 10,000 per tenant maximum for compliancy policies that also include policies
for Microsoft Purview Data Loss Prevention, Microsoft Purview Information
Barriers, and sensitivity labels.

Note

Exchange retention policies from messaging records management (MRM) are excluded
from this 10,000 maximum.
Maximum number of Microsoft 365 retention policies per tenant: 1,800
Maximum number of holds per mailbox: 25 is the recommended maximum before
performance might be impacted; 50 is the supported limit.


JOURNAL, TRANSPORT, AND INBOX RULE LIMITS

The following list includes limits that apply to journal rules, transport rules
(also known as organization-wide rules), and limits that apply to inbox rules.
Inbox rules are set up by individual users and applied to messages sent and
received by the individual user's mailbox.

 * Maximum number of journal rules: The maximum number of journal rules that can
   exist in the organization.

 * Maximum number of transport rules: The maximum number of rules that can exist
   in the organization.

 * Maximum size of an individual transport rule: The maximum number of
   characters that can be used in a single transport rule. The characters are
   used in the conditions, exceptions, and actions.

 * Character limit for all regular expressions used in all transport rules: The
   total number of characters used including all the regular expressions in all
   the transport rule conditions and exceptions in the organization. You can
   have a few rules that use long and complex regular expressions, or you can
   have many rules that use simple regular expressions.

 * Scanning limits for attachment content: The transport rule conditions let you
   examine the content of message attachments, but only the first 1 MB of the
   text extracted from an attachment is inspected. This 1 MB limit refers to the
   text extracted from the attachment, not to the file size of the attachment.
   For example, a 2 MB file may contain less than 1 MB of text, so all of the
   text would be inspected.

 * Maximum number of recipients added to a message by all transport rules: When
   a message is acted on by different transport rules, only a finite number of
   recipients can be added to the message. After the limit is reached, any
   remaining recipients aren't added to the message. Also, distribution groups
   can't be added to a message by a transport rule.

 * Forwardee limit: The maximum number of recipients that can be configured for
   an inbox or transport rule with a redirecting action. If a rule is configured
   to redirect a message to more than this number of recipients, the rule won't
   be applied and any message that satisfies the rule condition won't be
   redirected to any of the recipients listed in the rule.

 * Number of times a message is redirected: The number of times a message will
   be redirected, forwarded, or replied to automatically based on Inbox rules.
   For example, User A has an Inbox rule that redirects messages to User B,
   based on the sender. User B has an Inbox rule that forwards messages to User
   C based on keywords in the subject line. If a message satisfies both of these
   conditions, the message is only sent to User B; it's not forwarded to User C
   because only one redirection is allowed. In this case, the message is dropped
   without sending a non-delivery report (NDR) to User B indicating that the
   message wasn't delivered to User C. We make use of the
   X-MS-Exchange-Inbox-Rules-Loop header to determine the number of times that a
   message was redirected. This header remains also across Exchange
   organizational boundaries.

 * Number of times a message is redirected by transport rules: The number of
   times a message will be redirected based on transport rules. For example,
   Exchange organization Tailspin Toys have a transport rule to redirect every
   message that was sent to User A to User B, which is located in Exchange
   organization Contoso. Within Exchange organization Contoso, there's a
   transport rule in place to redirect every message that was sent to User B to
   User C, which is located in Exchange organization A. Datum Corporation. In
   this case, the message is dropped and a non-delivery report (NDR) with status
   code and reject message 550 5.7.128 TRANSPORT.RULES.RejectMessage; Transport
   rules loop count exceeded and message rejected is sent to User A. We make use
   of the X-MS-Exchange-Transport-Rules-Loop header to determine the number of
   times that a message was redirected by transport rules. This header remains
   also across Exchange organizational boundaries.


JOURNAL, TRANSPORT, AND INBOX RULE LIMITS

Feature Microsoft 365 Business Basic and Standard Microsoft 365 Business Premium
Microsoft 365 Enterprise E3/E5 Office 365 Enterprise E1 Office 365 Enterprise
E3/E5 Office 365 Enterprise F3 Maximum number of journal rules 300 rules 300
rules 300 rules 300 rules 300 rules 300 rules Maximum number of transport rules
300 rules 300 rules 300 rules 300 rules 300 rules 300 rules Maximum size of an
individual transport rule 8 KB 8 KB 8 KB 8 KB 8 KB 8 KB Character limit for all
regular expressions used in all transport rules 20 KB 20 KB 20 KB 20 KB 20 KB 20
KB Scanning limits for content of attachments 1 MB 1 MB 1 MB 1 MB 1 MB 1 MB
Maximum number of recipients added to a message by all transport rules 100
recipients 100 recipients 100 recipients 100 recipients 100 recipients 100
recipients Forwardee limit 10 recipients 10 recipients 10 recipients 10
recipients 10 recipients 10 recipients Number of times a message is redirected 1
redirection 1 redirection 1 redirection 1 redirection 1 redirection 1
redirection Number of times a message is redirected by transport rules 1
redirection 1 redirection 1 redirection 1 redirection 1 redirection 1
redirection Number of times a message is redirected 1 redirection 1 redirection
1 redirection 1 redirection 1 redirection 1 redirection Inbox rule 256kb1 256kb1
256kb1 256kb1 256kb1 256kb1

1 If a mailbox was migrated to Exchange Online, the inbox rule limit might be
set to the value that is lower than the default EXO value. If that is the case,
the inbox rule value can be increased. For instructions, see Modify the space
used by Inbox rules in Exchange Online.


JOURNAL, TRANSPORT, AND INBOX RULE LIMITS ACROSS STANDALONE OPTIONS

Feature Exchange Server Exchange Online Plan 1 Exchange Online Plan 2 Exchange
Online Kiosk Maximum number of journal rules No limit 50 rules 50 rules 50 rules
Maximum number of transport rules No limit 300 rules 300 rules 300 rules Maximum
size of an individual transport rule 40 KB 8 KB 8 KB 8 KB Character limit for
all regular expressions used in all transport rules No limit 20 KB 20 KB 20 KB
Maximum number of recipients added to a message by all transport rules No limit
100 recipients 100 recipients 100 recipients Forwardee limit No limit 10
recipients 10 recipients 10 recipients Number of times a message is redirected 3
redirections 1 redirection 1 redirection 1 redirection Number of times a message
is redirected by transport rules No limit 1 redirection 1 redirection 1
redirection


MAILBOX FOLDER LIMITS

These limits are intended to limit mailboxes to known dimensions that can be
supported in Exchange Online. The goal of these limits is to prevent an infinite
number of mailbox items per folder, an infinite number of folders per mailbox,
or an infinite number of public folders per Exchange Online organization. For
practical purposes, mailbox folder limits are in effect unlimited and sufficient
to support most Exchange Online mailboxes and on-premises mailboxes that are
migrated to Exchange Online.

 * Maximum number of messages per mailbox folder: Specifies the maximum number
   of messages for a mailbox folder. New messages can't be delivered or saved in
   a folder when this limit is reached.

 * Warning for number of messages per mailbox folder: Specifies the number of
   messages that a mailbox folder can hold before Exchange Online sends a
   warning message to the mailbox owner. When this quota is reached, warning
   messages are sent once a day.

 * Maximum number of messages per folder in the Recoverable Items folder:
   Specifies the maximum number of messages that can be contained in each folder
   in the Recoverable Items folder. When a folder exceeds this limit, it can't
   store new messages. For example, if the Deletions folder in the Recoverable
   Items folder has exceeded the message count limit and the mailbox owner
   attempts to permanently delete items from their mailbox, the deletion will
   fail.

 * Warning for number of messages per folder in the Recoverable Items folder:
   Specifies the number of messages that each folder in the Recoverable Items
   folder can hold before Exchange Online logs an event to the application event
   log.

 * Maximum number of subfolders per mailbox folder: Specifies the maximum number
   of subfolders that can be created in a mailbox folder. The mailbox owner
   won't be able to create a new subfolder when this limit is reached.

 * Warning for number of subfolders per mailbox folder: Specifies the number of
   subfolders that can be created in a mailbox folder before Exchange Online
   sends a warning message to the mailbox owner. When this quota is reached,
   warning messages are sent once a day.

 * Maximum folder hierarchy depth: Specifies the maximum number of levels in the
   folder hierarchy of a mailbox. The mailbox owner won't be able to create
   another level in the folder hierarchy of the mailbox folder when this limit
   is reached.

 * Warning for folder hierarchy depth: Specifies the number of levels in the
   folder hierarchy of a mailbox folder that can be created before Exchange
   Online sends a warning message to the mailbox owner. When this quota is
   reached, warning messages are sent once a day.

 * Maximum number of public folders: Specifies the maximum number of public
   folders in the complete public folder hierarchy. When this limit is reached,
   existing public folders must be deleted before new public folders can be
   created.

 * Maximum number of subfolders per public folder: Specifies the maximum number
   of subfolders that can be created in a public folder. New subfolders can't be
   created in a public folder when this limit is reached.

 * Warning for number of subfolders per public folder: Specifies the number of
   subfolders that can be created in a public folder before Exchange Online
   sends a warning message to the folder owner. If no owner exists, warning
   messages are sent to users with Owner permissions. When this quota is
   reached, warning messages are sent once a day.


MAILBOX FOLDER LIMITS

Feature Microsoft 365 Business Basic and Standard Microsoft 365 Business Premium
Microsoft 365 Enterprise E3/E5 Office 365 Enterprise E1 Office 365 Enterprise
E3/E5 Office 365 Enterprise F3 Maximum number of messages per mailbox folder 1
million 1 million 1 million 1 million 1 million 1 million Warning for number of
messages per mailbox folder 900,000 900,000 900,000 900,000 900,000 900,000
Maximum number of messages per folder in the Recoverable Items folder 3 million
3 million 3 million 3 million 3 million 3 million Storage quota for Recoverable
Items folder in primary mailbox (not on hold) 30 GB 30 GB 30 GB 30 GB 30 GB 30
GB Storage quota for Recoverable Items folder in primary mailbox (on hold) 100
GB 100 GB 100 GB 100 GB 100 GB 100 GB Storage quota for Recoverable Items folder
in archive mailbox (not on hold) 30 GB 1.5 TB2 1.5 TB2 30 GB 1.5 TB2 30 GB
Storage quota for Recoverable Items folder in archive mailbox (on hold) 100 GB1
1.5 TB2 1.5 TB2 100 GB1 1.5 TB2 100 GB1 Warning for number of messages per
folder in the Recoverable Items folder 2.75 million 2.75 million 2.75 million
2.75 million 2.75 million 2.75 million Maximum number of subfolders per mailbox
folder 10,0003 10,0003 10,0003 10,0003 10,0003 10,0003 Warning for number of
subfolders per mailbox folder 9000 9000 9000 9000 9000 9000 Maximum folder
hierarchy depth 300 300 300 300 300 300 Warning for folder hierarchy depth 250
250 250 250 250 250 Maximum number of public folders 500,000 500,000 500,000
500,000 500,000 Not available Maximum number of subfolders per public folder
10,000 10,000 10,000 10,000 10,000 Not available Warning for number of
subfolders per public folder 9000 9000 9000 9000 9000 Not available

1 This is the storage quota for the Recoverable Items folder, not the quota for
the entire archive mailbox. The storage quota for the archive mailbox is 1.5 TB
for users with an Exchange Online Plan 2 license or for users who have both an
Exchange Online Plan 1 and an Exchange Online Archiving license. For information
about increasing the Recoverable Items quota, see Increase the Recoverable Items
quota for mailboxes on hold.
2 The initial storage quota for the Recoverable Items folder in an archive
mailbox is 100 GB. When auto-expanding archiving is turned on, additional
storage is automatically added when the storage capacity for the Recoverable
Items folder is reached. For more information, see Overview of auto-expanding
archiving. See the Microsoft 365 Roadmap for details about availability of
auto-expanding archiving.
3 This is a store limit; it is one of the mailbox shape constraints. There can
be only 10,000 direct child folders for any given parent. This applies
regardless of migration or other clients creating folders.


MAILBOX FOLDER LIMITS ACROSS STANDALONE PLANS

Feature Exchange Server Exchange Online Plan 1 Exchange Online Plan 2 Exchange
Online Kiosk Maximum number of messages per mailbox folder No limit1 1 million 1
million 1 million Warning for number of messages per mailbox folder No limit
900,000 900,000 900,000 Maximum number of messages per folder in the Recoverable
Items folder No limit 3 million 3 million 3 million Storage quota for
Recoverable Items folder in primary mailbox (not on hold) 30 GB 30 GB 30 GB 30
GB Storage quota for Recoverable Items folder in primary mailbox (on hold) 100
GB 100 GB 100 GB 100 GB Storage quota for Recoverable Items folder in archive
mailbox (not on hold) 30 GB 30 GB 30 GB 30 GB Storage quota for Recoverable
Items folder in archive mailbox (on hold) 100 GB2 100 GB2 1.5 TB3 1.5 TB3
Warning for number of messages per folder in the Recoverable Items folder No
limit 2.75 million 2.75 million 2.75 million Maximum number of subfolders per
mailbox folder No limit 1000 1000 1000 Warning for number of subfolders per
mailbox folder No limit 900 900 900 Maximum folder hierarchy depth No limit 300
300 300 Warning for folder hierarchy depth No limit 250 250 250 Maximum number
of public folders 1,000,000 100,000 100,000 Not available Maximum number of
subfolders per public folder N/A 1,000 1,000 Not available Warning for number of
subfolders per public folder N/A 900 900 Not available

1 Microsoft recommends no more than 1,000,000 messages per mailbox folder.
2 If the auto-expanding archive is not enabled, this is the storage quota for
the Recoverable Items folder, not the quota for the entire archive mailbox. For
information about increasing the Recoverable Items quota, see Increase the
Recoverable Items quota for mailboxes on hold. If the auto-expanding archiving
feature is enabled, the storage quota for the user's archive mailbox, including
the Recoverable Items folder, is 1.5 TB. This applies to users with an Exchange
Online Plan 2 license or for users who have both an Exchange Online Plan 1 and
an Exchange Online Archiving license.
3 The initial storage quota for the Recoverable Items folder in an archive
mailbox is 100 GB. When auto-expanding archiving is turned on, additional
storage is automatically added when the storage capacity for the Recoverable
Items folder is reached. For more information, see Overview of auto-expanding
archiving. See the Microsoft 365 Roadmap for details about availability of
auto-expanding archiving.


MAILBOX STORAGE LIMITS

The amount of mailbox storage available is determined by the mailbox type and
the user's subscription license. Administrators can reduce maximum mailbox sizes
per user or globally.

Note

Using journaling, transport rules, or auto-forwarding rules to copy messages to
an Exchange Online mailbox for the purposes of archiving is not permitted. A
user's archive mailbox is intended for just that user. Microsoft reserves the
right to deny additional archive storage space in instances where a user's
archive mailbox is used to store archive data for other users or in other cases
of inappropriate use.


STORAGE LIMITS

Feature Microsoft 365 Business Basic and Standard Microsoft 365 Business Premium
Microsoft 365 Enterprise E3/E5 Office 365 Enterprise E1 Office 365 Enterprise
E3/E5 Office 365 Enterprise F3 User mailboxes 50 GB 50 GB 100 GB 50 GB 100 GB 2
GB Archive mailboxes7,8 50 GB 1.5 TB1 1.5 TB1 50 GB 1.5 TB1 Not available4
Shared mailboxes10 50 GB2 50 GB2 50/100 GB2,9 50 GB2 50/100 GB2,9 50 GB2
Resource mailboxes 50 GB3 50 GB3 50 GB3,9 50 GB3 50 GB3,9 50 GB3 Public folder
mailboxes5 100 GB6 100 GB6 100 GB6 100 GB6 100 GB6 100 GB6 Group mailboxes 50 GB
50 GB 50 GB 50 GB 50 GB 50 GB

1 Each user initially receives 100 GB of storage in the archive mailbox. When
auto-expanding archiving is turned on, additional storage is automatically added
when the 100 GB storage capacity is reached. Additional storage space is added
incrementally until the archive storage capacity reaches 1.5 TB. For more
information, see Overview of auto-expanding archiving.
2 To access a shared mailbox, a user must have an Exchange Online license, but
the shared mailbox doesn't require a separate license. Without a license, shared
mailboxes are limited to 50 GB. To increase the size limit to 100 GB, the shared
mailbox must be assigned an Exchange Online Plan 2 license. If Exchange Online
Plan 1 license with an Exchange Online Archiving add-on license is assigned,
this will let you enable auto-expanding archiving for additional archive storage
capacity. Similarly, if you want to place a shared mailbox on litigation hold,
the shared mailbox must have an Exchange Online Plan 2 license or an Exchange
Online Plan 1 license with an Exchange Online Archiving add-on license. If you
want to apply advanced features such as Microsoft Defender for Office 365,
Microsoft Purview eDiscovery (Premium), or retention policies, the shared
mailbox must be licensed for those feature(s).
3 Resource mailboxes don't require a license. However, without a license,
resource mailboxes are limited to 50 GB. To increase the mailbox size, an E3 or
E5 license must be assigned. This will increase the mailbox to 100 GB.
4 Archive mailboxes aren't included in Exchange Online Kiosk. However, they can
be purchased as an add-on through Exchange Online Archiving. For more
information, see the Exchange Online Archiving service description.
5 The default individual public folder size limit is 2GB. You can change the
size limit individually on each folder or change the default size limit defined
in the organization’s configuration to make the change effective for all folders
in the organization. Note: Maximum recommended size of individual public folder
is 25 GB. If an individual public folder grows above 25 GB, it will have issues
during auto-split process.
6 You are limited to 1,000 public folder mailboxes, and the maximum total size
of all public folder mailboxes is 100 TB. Hierarchy Serving mailboxes are
limited to 100 public folder mailboxes.
7 Archive mailboxes can only be used to archive mail for a single user or entity
(such as a shared mailbox) for which a license has been applied. Using archive
mailboxes as a means of storing mail from multiple users or entities is
prohibited. For example, an IT administrator can't create a shared mailbox and
have users copy it (through the Cc or Bcc field, or through a transport rule)
for the explicit purpose of archiving. Note that a shared mailbox that multiple
people use does not actually store email for those individual users. Multiple
users have access, and they send email as the shared mailbox. Therefore, the
only emails stored in the shared mailbox are those sent to or from it, as the
shared mailbox.
8 If you have created a retention policy in Exchange Online, messages will be
automatically moved to a user's archive mailbox only if the user's primary
mailbox is larger than 10 MB. The retention policy will not run automatically
for mailboxes that are smaller than 10 MB.
9 Shared and resource mailboxes don't require a license. However, without a
license, these mailboxes are limited to 50 GB. To increase the mailbox size, an
E3 or E5 license must be assigned. This will increase the mailbox to 100 GB.
10 By default, shared mailboxes have an associated active user account with a
system-generated (unknown) password. To block sign-in for the associated shared
mailbox account, see Block sign-in for the shared mailbox account.


STORAGE LIMITS ACROSS STANDALONE PLANS

Feature Exchange Server Exchange Online Plan 1 Exchange Online Plan 2 Exchange
Online Kiosk User mailboxes 2 GB1 50 GB 100 GB 2 GB Archive mailboxes8,9 100 GB1
50 GB 1.5 TB2 Not available5 Shared mailboxes11 2 GB1 50 GB3 50 GB3,10 50 GB3
Resource mailboxes 2 GB1 50 GB4 50 GB4,10 50 GB4 Public folder mailboxes 2 GB6
50 GB7 100 GB7 Not available Group mailboxes 50 GB 50 GB 50 GB 50 GB

1 This is the default mailbox size for Exchange Server organizations.
Administrators can change this value for their organization. There isn't a
maximum storage limit for on-premises mailboxes.
2 Each user initially receives 100 GB of storage in the archive mailbox. When
auto-expanding archiving is turned on, additional storage is automatically added
when the 100 GB storage capacity is reached. Additional storage space is added
incrementally until the archive storage capacity reaches 1.5 TB. For more
information, see Overview of auto-expanding archiving. See the Microsoft 365
Roadmap for details about availability for auto-expanding archiving.
3 To access a shared mailbox, a user must have an Exchange Online license, but
the shared mailbox doesn't require a separate license. Without a license, shared
mailboxes are limited to 50 GB. To increase the size limit to 100 GB, the shared
mailbox must be assigned an Exchange Online Plan 2 license. The Exchange Online
Plan 1 license with an Exchange Online Archiving add-on license will increase
the size of the Archive mailbox. This will also let you enable auto-expanding
archiving for up to 1.5 TB of archive storage capacity. Similarly, if you want
to place a shared mailbox on litigation hold, the shared mailbox must have an
Exchange Online Plan 2 license or an Exchange Online Plan 1 license with an
Exchange Online Archiving add-on license. If you want to apply advanced features
such as Microsoft Defender for Office 365, eDiscovery (Premium), or automatic
retention policies, the shared mailbox must be licensed for those feature(s).
4 Resource mailboxes don't require a license. However, without a license,
resource mailboxes are limited to 50 GB. To increase the mailbox size, an
Exchange Online Plan 2 license must be assigned. This will increase the mailbox
to 100 GB.
5 Archive mailboxes aren't included in Exchange Online Kiosk. However, they can
be purchased as an add-on through Exchange Online Archiving. For more
information, please see the Exchange Online Archiving service description.
6 This is the default mailbox size for Microsoft Exchange Server organizations.
Administrators can change this value for their organization. In Exchange Server,
you are limited to 100 public folder mailboxes, and the maximum total size of
all public folder mailboxes is 50 TB.
7 In Exchange Online, you are limited to 1,000 public folder mailboxes, and the
maximum total size of all public folder mailboxes is 50 TB.
8 Archive mailboxes can only be used to archive mail for a single user or entity
for which a license has been applied. Using an archive mailbox as a means to
store mail from multiple users or entities is prohibited. For example, IT
administrators can't create shared mailboxes and have users copy (through the Cc
or Bcc field, or through a transport rule) a shared mailbox for the explicit
purpose of archiving.
9 If you have created a retention policy in Exchange Online, messages will be
automatically moved to a user's archive mailbox only if the user's primary
mailbox is larger than 10 MB. The retention policy will not run automatically
for mailboxes that are smaller than 10 MB.
10 Shared and resource mailboxes don't require a license. However, without a
license, these mailboxes are limited to 50 GB. To increase the mailbox size, an
Exchange Online Plan 2 license must be assigned. This will increase the mailbox
to 100 GB.
11 By default, shared mailboxes have an associated active user account with a
system-generated (unknown) password. To block sign-in for the associated shared
mailbox account, see Block sign-in for the shared mailbox account.


MESSAGE LIMITS

The following limits are applied to every email message.

 * Message size limit: Message size limits are necessary to prevent large
   messages from blocking delivery of other messages and affecting service
   performance for all users. These limits include attachments, and apply
   organization-wide to all messages (inbound, outbound, and internal). Messages
   larger than this limit won't be delivered, and the sender will receive a
   non-delivery report (NDR). While message size limits can be configured up,
   down, or on a per-user basis, administrators can also create transport rules
   to limit the maximum size of any individual attachment. To learn more, see
   Microsoft supports larger email messages.
   
   Note
   
   Some email clients may have lower message size limits or may limit the size
   of an individual file attachment to a value that is less than the Exchange
   Online message size limit.

 * Message header size limit: Specifies the maximum size of all message header
   fields in a message. The current limit is 256 KB. If the total size of all
   message headers exceeds 256 KB, Exchange Online will reject the message with
   error "552 5.3.4 Header size exceeds fixed maximum size." The size of the
   message body or attachments isn't considered. Because the header fields are
   plain text, the size of the header is determined by the number of characters
   in each header field and by the total number of header fields. Each text
   character consumes 1 byte.

 * Subject length limit: The maximum number of text characters allowed in the
   subject line of an email message.

 * File attachments limit: The maximum number of file attachments allowed in an
   email message. Even if the total size of all the file attachments doesn't
   violate the message size limit, there's still a limit on how many attachments
   are allowed in the message. This limit is controlled by the multipart message
   limit.

 * File attachment size limit: The maximum file size of a single attachment.
   
   Note
   
   This is the maximum file size of a single attachment. Individual client
   programs, including Outlook on the web, may limit the size of attachments
   below this maximum. Exchange ActiveSync does not implement attachment size
   limits on an individual attachment basis. The total size of all attachments
   to an Exchange ActiveSync message must be less than the message size limit.

 * Multipart message limit: The maximum number of message body parts that are
   allowed in a MIME multipart message. This limit also controls the maximum
   number of file attachments that are allowed in a message.

 * Embedded message depth limit: The maximum number of forwarded email messages
   that are allowed in an email message.


MESSAGE LIMITS

Feature Microsoft 365 Business Basic and Standard Microsoft 365 Business Premium
Microsoft 365 Enterprise E3/E5 Office 365 Enterprise E1 Office 365 Enterprise
E3/E5 Office 365 Enterprise F3 Message size limit - Outlook 150 MB1,2 150 MB1,2
150 MB1,2 150 MB1,2 150 MB1,2 150 MB1,2 Message size limit - OWA 112 MB1,3 112
MB1,3 112 MB1,3 112 MB1,3 112 MB1,3 112 MB1,3 Message size limit - Outlook for
Mac 150 MB1,2 150 MB1,2 150 MB1,2 150 MB1,2 150 MB1,2 150 MB1,2 Message size
limit - migration 150 MB1,4 150 MB1,4 150 MB1,4 150 MB1,4 150 MB1,4 150 MB1,4
Message size limit - Outlook for iOS and Android 33 MB 33 MB 33 MB 33 MB 33 MB
33 MB Size limit for encrypted messages (for subscribers using Microsoft Purview
Message Encryption with new capabilities)5 25 MB 25 MB 25 MB 25 MB 25 MB 25 MB
Size limit for encrypted messages (for subscribers using Message Encryption
legacy version)5 25 MB 25 MB 25 MB 25 MB 25 MB 25 MB Subject length limit 255
characters 255 characters 255 characters 255 characters 255 characters 255
characters File attachments limit 250 attachments 250 attachments 250
attachments 250 attachments 250 attachments 250 attachments File attachment size
limit - Outlook 150 MB 150 MB 150 MB 150 MB 150 MB 150 MB File attachment size
limit - OWA 112 MB3,6 112 MB3,6 112 MB3,6 112 MB3,6 112 MB3,6 112 MB3,6 File
attachment size limit - Outlook for Mac 150 MB 150 MB 150 MB 150 MB 150 MB 150
MB File attachment size limit - New Outlook for Mac 33 MB 33 MB 33 MB 33 MB 33
MB 33 MB File attachment size limit - Outlook for iOS and Android 33 MB 33 MB 33
MB 33 MB 33 MB 33 MB Multipart message limit 250 parts 250 parts 250 parts 250
parts 250 parts 250 parts Embedded message depth limit 30 embedded messages 30
embedded messages 30 embedded messages 30 embedded messages 30 embedded messages
30 embedded messages

1 The default maximum message size for Microsoft mailboxes is 35 MB for sending
and 36 MB for receiving. Microsoft administrators can specify a custom limit
between 1 MB and 150 MB. However, the size of message you can send or receive
also depends on what your email client or solution supports. For more
information about customizing the maximum allowed message size for your
organization, see Microsoft supports larger email messages.
2 You can send and receive up to 150 MB messages between users (where the
message never leaves the Microsoft datacenters). Messages that are routed
outside of the Microsoft datacenters are subject to an additional 33%
translation encoding increase, in which case the maximum message size is 112 MB.
3 OWA accounts for the possibility that your message may be subject to the 33%
encoding increase and restricts the size of message you can send to 25% less
than the configured setting. For example, if you customize your settings for a
100 MB maximum message size, you can send messages no larger than 75 MB.
4 The sizes of messages to be moved into Exchange Online are computed by
Exchange Online. Versions of Exchange prior to Exchange Server may report a
smaller item size. This limit applies to move-based migrations using any
supported Exchange Mailbox Replication Service. Other migration methods
(Cutover, Staged, IMAP, PST) and other third-party tools are limited by the
general message size limit.
5 For information about OME with new capabilities, see Set up new Message
Encryption capabilities built on top of Azure Information Protection.
6 Classic file attachments have a limit of 112 MB, but OneDrive file attachments
can be up to 2 GB.


MESSAGE LIMITS ACROSS STANDALONE OPTIONS

Feature Exchange Server Exchange Online Plan 1 Exchange Online Plan 2 Exchange
Online Kiosk Message size limit - Outlook 10 MB4 150 MB1,2 150 MB1,2 150 MB2
Message size limit - OWA 10 MB4 112 MB1,3 112 MB1,3 150 MB1,2 Message size limit
- Outlook for Mac 10 MB4 150 MB 150 MB Message size limit - migration Not
applicable 150 MB5 150 MB5 150 MB5 Message size limit - Outlook for iOS and
Android 25 MB 33 MB 33 MB 33 MB Size limit for encrypted messages (for
subscribers using Message Encryption with new capabilities)6 25 MB 25 MB 25 MB
25 MB Size limit for encrypted messages (for subscribers using Message
Encryption legacy version)6 25 MB 25 MB 25 MB 25 MB Subject length limit 255
characters 255 characters 255 characters 255 characters File attachments limit
1024 attachments4 250 attachments 250 attachments 250 attachments File
attachment size limit - Outlook 35 MB4 150 MB 150 MB 150 MB File attachment size
limit - OWA 35 MB4 112 MB3 112 MB3 112 MB3 File attachment size limit - Outlook
for Mac 35 MB4 150 MB 150 MB 35 MB File attachment size limit - Outlook for iOS
and Android 25 MB 33 MB 33 MB 33 MB Multipart message limit 250 parts 250 parts
250 parts 250 parts Embedded message depth limit 30 embedded messages 30
embedded messages 30 embedded messages 30 embedded messages

1 Microsoft administrators can specify a custom limit between 1 MB and 150 MB.
However, the size of message you can send or receive also depends on what your
email client or solution supports. For more information about customizing the
maximum allowed message size for your organization, see Microsoft supports
larger email messages.
2 You can send and receive up to 150 MB messages between users (where the
message never leaves the Microsoft datacenters). Messages that are routed
outside of the Microsoft datacenters are subject to an additional 33%
translation encoding increase, in which case the maximum message size is 112 MB.
3 OWA accounts for the possibility that your message may be subject to the 33%
encoding increase and restricts the size of message you can send to 25% less
than the configured setting. For example, if you customize your settings for a
100 MB maximum message size, you can send messages no larger than 75 MB.
4 This is the default limit for Exchange Server organizations. Administrators
can change this value for their organization.
5 The size of messages to be moved into Exchange Online is computed by Exchange
Online. Versions of Exchange prior to Exchange Server may report a smaller item
size.
6 For information about OME with new capabilities, see Set up new Message
Encryption capabilities built on top of Azure Information Protection.


MODERATION LIMITS

These limits control the moderation settings that are used for message approval
applied to distribution groups and transport rules.

 * Maximum size of the arbitration mailbox: If the arbitration mailbox exceeds
   this limit, messages that require moderation are returned to the sender in a
   non-delivery report (NDR).

 * Maximum number of moderators: The maximum number of moderators that you can
   assign to a single moderated distribution group or that can be added to a
   message using a single transport rule. Note that you can't specify a
   distribution group as a moderator.

 * Expiration for messages waiting for moderation: By default, a message waiting
   for moderation expires after two days, and admins can't extend this interval.
   However, the processing of expired moderated messages runs every seven days.
   This means that a moderated message can expire at any time between two and
   nine days.

 * Maximum rate for expired moderation notification messages: This limit sets
   the maximum number of notification messages for expired moderated messages in
   a one-hour period. This limit is placed on each mailbox database in the
   datacenter.

During periods of heavy usage, some senders may not receive notification
messages for moderated messages that have expired. However, these notifications
are still discoverable using delivery reports.


MODERATION LIMITS

Feature Microsoft 365 Business Basic and Standard Microsoft 365 Business Premium
Microsoft 365 Enterprise E3/E5 Office 365 Enterprise E1 Office 365 Enterprise
E3/E5 Office 365 Enterprise F3 Maximum size of the arbitration mailbox 10 GB 10
GB 10 GB 10 GB 10 GB 10 GB Maximum number of moderators 10 moderators 10
moderators 10 moderators 10 moderators 10 moderators 10 moderators Expiration
for messages waiting for moderation 2 days 2 days 2 days 2 days 2 days 2 days
Maximum rate for expired moderation notification messages 300 expiration
notifications per hour 300 expiration notifications per hour 300 expiration
notifications per hour 300 expiration notifications per hour 300 expiration
notifications per hour 300 expiration notifications per hour


MODERATION LIMITS ACROSS STANDALONE OPTIONS

Feature Exchange Server Exchange Online Plan 1 Exchange Online Plan 2 Exchange
Online Kiosk Maximum size of the arbitration mailbox No limit1 10 GB 10 GB 10 GB
Maximum number of moderators No limit 10 moderators 10 moderators 10 moderators
Expiration for messages waiting for moderation 5 days1 2 days 2 days 2 days
Maximum rate for expired moderation notification messages 300 expiration
notifications per hour 300 expiration notifications per hour 300 expiration
notifications per hour 300 expiration notifications per hour

1 This is the default limit for Exchange Server organizations. Administrators
can change this value for their organization.


RECEIVING AND SENDING LIMITS

Receiving and sending limits are applied to combat spam and mass-mailing worms
or viruses. These limits help to protect the health of our systems and keep our
users safe.


RECEIVING LIMITS

Receiving limits apply to the number of messages that an Exchange Online user,
group, or public folder can receive.

 * Receiving limit: This limit counts the number of messages per hour from any
   and all sources. This includes messages from internal senders, messages from
   the internet, and messages from on-premises servers. When the receiving limit
   has been exceeded on a mailbox, messages sent to the mailbox from the
   internet or on-premises senders will be returned to the sender in a
   non-delivery report (also known as an NDR or bounce message) stating that the
   mailbox has exceeded the maximum delivery threshold. Messages from internal
   senders will count against the limit, but won't be blocked if the receiving
   limit has been exceeded. After an hour, the limit will refresh and the
   mailbox will be able to receive messages.
 * Sender-recipient pair limit: This limit applies to the number of messages per
   hour from a single sender. This is set to a ratio of the overall receiving
   limit to protect against single-sender mail storms.

Feature Microsoft 365 Business Basic and Standard Microsoft 365 Business Premium
Microsoft 365 Enterprise E3/E5 Office 365 Enterprise E1 Office 365 Enterprise
E3/E5 Office 365 Enterprise F3 Receiving limit 3,600 messages per hour 3,600
messages per hour 3,600 messages per hour 3,600 messages per hour 3600 messages
per hour 3600 messages per hour Messages received from single sender 33% of
receiving limit 33% of receiving limit 33% of receiving limit 33% of receiving
limit 33% of receiving limit 33% of receiving limit


SENDING LIMITS

Sending limits apply to the number of recipients, number of messages, and number
of recipients per message that a user can send from their Exchange Online
account.

For distribution groups stored in an organization's address book, the group is
counted as one recipient. For distribution groups stored in the Contacts folder
of a mailbox, the members of the group are counted individually.

Sending from another mailbox via permissions is counted for the delegate with
rights and not the mailbox that is being sent from.

 * Recipient rate limit: To discourage the delivery of unsolicited bulk
   messages, Exchange Online has recipient limits that prevent users and
   applications from sending large volumes of email. These limits are applied
   per-user to all outbound and internal messages.
   
   Note
   
   Exchange Online customers who need to send legitimate bulk commercial email
   (for example, customer newsletters) should use third-party providers that
   specialize in these services.

 * Recipient limit: This is the maximum number of recipients allowed in the To:,
   Cc:, and Bcc: fields for a single email message.
   
   Note
   
   For the purposes of the recipient rate limit and the recipient limit, a
   distribution group that is stored in the organization's shared address book
   counts as one recipient. In a personal distribution list, each recipient is
   counted separately.

 * Recipient proxy address limit: The recipient proxy address limit is the
   maximum number of aliases (email addresses) that a recipient mailbox can
   have.

 * Message rate limit: Message rate limits determine how many messages a user
   can send from their Exchange Online account within a specified period of
   time. This limit helps prevent over consumption of system resources by a
   single sender. If a user submits messages at a rate that exceeds the limit
   via SMTP client submission, the messages will be rejected and the client will
   need to retry.

SENDING LIMITS

Feature Microsoft 365 Business Basic and Standard Microsoft 365 Business Premium
Microsoft 365 Enterprise E3/E5 Office 365 Enterprise E1 Office 365 Enterprise
E3/E5 Office 365 Enterprise F3 Recipient rate limit1 10,000 recipients per day
10,000 recipients per day 10,000 recipients per day 10,000 recipients per day
10,000 recipients per day 10,000 recipients per day Recipient limit2
Customizable up to 1000 recipients Customizable up to 1000 recipients
Customizable up to 1000 recipients Customizable up to 1000 recipients
Customizable up to 1000 recipients Customizable up to 1000 recipients Recipient
proxy address limit3 300 300 300 300 300 300 Message rate limit4 30 messages per
minute 30 messages per minute 30 messages per minute 30 messages per minute 30
messages per minute 30 messages per minute

1 After the recipient rate limit is reached, messages can't be sent from the
mailbox until the number of recipients that were sent messages in the past 24
hours drops below the limit. For example, a user sends an email message to 5000
recipients at 09:00 AM, then sends another message to 2500 recipients at 10:00
AM, and then sends another message to 2500 recipients at 11:00 AM, hitting the
limit of 10,000 messages. The user won't be able to send messages again until
09:00 AM the next day.
2 You can customize recipient limits between 1 and 1000 for existing mailboxes
and for new mailboxes that will be created in the future. Edit the recipient
limit on existing mailboxes individually or in bulk using the Exchange admin
center and customize the default setting for new mailboxes via Remote
PowerShell. For more information, see Customizable recipient limits in Office
365.
3 These numbers can vary slightly since the limit is based on number of
characters so the number of email addresses will vary depending on how long they
are. As a rule of thumb, it is safer to assume that the limit of smtp addresses
in ProxyAddresses is approximately 300 addresses to leave room for future growth
of the object and its populated attributes.
4 When outbound message volumes surpass the message rate limit, any excess in
message submission will be throttled and successively carried over to the
following minutes. This will typically not block the sender's account, but
Exchange Online isn't suited to accommodate bulk-mailing scenarios. For this use
case, options 2 and 3 here are recommended instead.

SENDING LIMITS ACROSS STANDALONE OPTIONS

Feature Exchange Server Exchange Online Plan 1 Exchange Online Plan 2 Exchange
Online Kiosk Recipient rate limit No limit1 10,000 recipients per day2 10,000
recipients per day2 10,000 recipients per day2 Recipient limit 1000 recipients1
1000 recipients 1000 recipients 1000 recipients Recipient proxy address limit
400 400 400 400 Message rate limit No limit 30 messages per minute 30 messages
per minute 30 messages per minute

1 This is the default limit for Exchange Server organizations. Administrators
can change this value for their organization.
2 After the recipient rate limit is reached, messages can't be sent from the
mailbox until the number of recipients that were sent messages in the past 24
hours drops below the limit. For example, a user sends an email message to 5000
recipients at 09:00 AM, then sends another message to 2500 recipients at 10:00
AM, and then sends another message to 2500 recipients at 11:00 AM, hitting the
limit of 10,000 messages. The user won't be able to send messages again until
09:00 AM the next day.

SENDING AND RECEIVING MEETING INVITE LIMITS

Recipient limits in Microsoft 365 when sending meeting invitations or updates is
2,500 recipients (maximum number of recipients on any outgoing meeting message -
whether a new invitation, a meeting update, or a meeting cancellation). This
maximum applies only to meeting messages. This ensures that you’ll always be
able to update or cancel the meeting and still see the list of attendees and
responses. For more information, go to Scheduling meetings with hundreds of
attendees (microsoft.com).


REPORTING AND MESSAGE TRACE LIMITS

For reporting and message trace limits, see the "Reporting and message trace
data availability and latency" section in Reporting and message trace in
Exchange Online Protection.


RETENTION LIMITS

These limits control the length of time that items in specific folders in the
Inbox can be accessed.

 * Deleted Items folder retention period: The maximum number of days that items
   can remain in the Deleted Items folder before they're automatically removed.

 * Retention period for items removed from the Deleted Items folder: The maximum
   numbers of days that items removed from the Deleted Items folder are retained
   before they're permanently deleted.

 * Junk Email folder retention period: The maximum number of days that items can
   remain in the Junk Email folder before they're automatically removed.

Note

A soft-deleted user mailbox—a mailbox deleted using the Microsoft 365 admin
center or the Remove-Mailbox cmdlet in Exchange Online PowerShell and that is
still in the Azure Active Directory recycle bin—is recoverable within 30 days.


RETENTION LIMITS

Feature Microsoft 365 Business Basic and Standard Microsoft 365 Business Premium
Microsoft 365 Enterprise E3/E5 Office 365 Enterprise E1 Office 365 Enterprise
E3/E5 Office 365 Enterprise F3 Deleted Items folder retention period No limit1
No limit1 No limit1 No limit1 No limit1 No limit1 Retention period for items
removed from the Deleted Items folder 14 days1 14 days1 14 days1 14 days1 14
days1 14 days1 Junk Email folder retention period 30 days 30 days 30 days 30
days 30 days 30 days

1 This is the default value for Microsoft 365 organizations. Administrators can
change this value to a maximum of 30 days for mailboxes in their organization.


RETENTION LIMITS ACROSS STANDALONE OPTIONS

Feature Exchange Server Exchange Online Plan 1 Exchange Online Plan 2 Exchange
Online Kiosk Deleted Items folder retention period No limit1 No limit1 No limit1
No limit1 Retention period for items removed from the Deleted Items folder 14
days1 14 days2 14 days2 14 days2 Junk Email folder retention period 2 years1 30
days 30 days 30 days

1 This is the default limit. Administrators can change this value for their
organization.
2 This is the default value for Exchange Online organizations. Administrators
can change this value to a maximum of 30 days for mailboxes in their
organization.






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