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Exchange Online Limits

Office 365
 

Applies to: Office 365

Topic Last Modified: 2015-05-26

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

ImportantImportant:
  • The limits applied to a Microsoft Office 365 organization may differ depending on how long the organization has been enrolled in the service. When a limit is changed in the Microsoft datacenters, 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.

  • Address list limit The maximum number of address lists that can be created in an Exchange Online or Exchange Server 2013 organization. This number includes the default address lists in Exchange Online, such as All Contacts and All Groups.

  • Offline address book limit The maximum number of offline address books (OAB) that can be created in an Exchange Online or Exchange Server 2013 organization.

  • Address book policies limit The maximum number of address book policies (ABP) that be created in an Exchange Online or Exchange Server 2013 organization.

  • Global address lists The maximum number of global address lists (GAL) that be created in an Exchange Online or Exchange Server 2013 organization.

 

Feature

Office 365 Business Essentials

Office 365 Business Premium

Office 365 Enterprise E1

Office 365 Education E1

Office 365 Government E1

Office 365 Enterprise E3

Office 365 Education E3

Office 365 Government E3

Office 365 Enterprise E4

Office 365 Education E4

Office 365 Government E4

Office 365 Enterprise K1

Office 365 Government K1

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

 

Feature

Exchange Server 2013

Exchange Online Plan 1

Exchange Online Plan 2

Exchange Online Kiosk

Address list limit

1000

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

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.

NoteNote:
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 unlimited archiving in instances where a user’s archive mailbox is used to store archive data for other users.

 

Feature

Office 365 Business Essentials

Office 365 Business Premium

Office 365 Enterprise E1

Office 365 Education E1

Office 365 Government E1

Office 365 Enterprise E3

Office 365 Education E3

Office 365 Government E3

Office 365 Enterprise E4

Office 365 Education E4

Office 365 Government E4

Office 365 Enterprise K1

Office 365 Government K1

User mailboxes

50 GB

50 GB

50 GB

50 GB

50 GB

2 GB

Archive mailboxes9, 10

50 GB1

50 GB1

50 GB1

No limit2

No limit2

Not available6

Shared mailboxes

50 GB3

50 GB3

50 GB3

50 GB3

50 GB3

Not available4

Resource mailboxes

50 GB5

50 GB5

50 GB5

50 GB5

50 GB5

50 GB5

Site mailboxes7

5 GB

5 GB

5 GB

5 GB

5 GB

Not available

Public folder mailboxes

50 GB8

50 GB8

50 GB8

50 GB8

50 GB8

Not available

NoteNote:
1 Each subscriber receives 50 GB of total storage, which the user can divide between the primary mailbox and the personal archive. As such, the size of the personal archive can’t exceed 50 GB.
2   Each subscriber receives 50 GB of storage in the primary mailbox, plus unlimited storage in the archive mailbox. A default quota of 100 GB is set on the archive mailbox, which will generally accommodate reasonable use, including the import of one user’s historical email. In the unlikely event that a user reaches this quota, a call to Office 365 support is required. Administrators can’t increase or decrease this quota.
3   A user must have an Exchange Online license in order to access a shared mailbox. Shared mailboxes don’t require a separate license.
4   Office 365 Enterprise K1 and Office 365 Government K1 users can’t access shared mailboxes.
5   Resource mailboxes don’t require a license.
6   In-Place Archive isn’t included in Exchange Online Kiosk. However, it can be purchased as an add-on through Exchange Online Archiving. For more information, please see the Exchange Online Archiving Service Description.
7   Site mailboxes are created and managed in SharePoint Online. For more information, see Prepare for using site mailboxes in Office 365.
8   You are limited to 50 public folder mailboxes, and the maximum total size of all public folder mailboxes is 2.5 TB.
9   In-Place Archive can only be used to archive mail for a single user or entity for which a license has been applied. Using an In-Place Archive 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.
10   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.

 

Feature

Exchange Server 2013

Exchange Online Plan 1

Exchange Online Plan 2

Exchange Online Kiosk

User mailboxes

2 GB1

50 GB

50 GB

2 GB

Archive mailboxes10, 11

No limit

50 GB2

No limit3

Not available6

Shared mailboxes

2 GB1

50 GB4

50 GB4

Not available7

Resource mailboxes

2 GB1

50 GB5

50 GB5

50 GB5

Public folder mailboxes

2 GB8

50 GB9

50 GB9

Not available

NoteNote:
1   This is the default mailbox size for Exchange Server 2013 organizations. Administrators can change this value for their organization. There isn’t a maximum storage limit for on-premises mailboxes.
2   Each subscriber receives 50 GB of total storage, which the user can divide between the primary mailbox and the personal archive. As such, the size of the personal archive can’t exceed 50 GB.
3   Each subscriber receives 50 GB of storage in the primary mailbox, plus unlimited storage in the archive mailbox. A default quota of 100 GB is set on the archive mailbox, which will generally accommodate reasonable use, including the import of one user’s historical email. In the unlikely event that a user reaches this quota, a call to Office 365 support is required. Administrators can’t increase or decrease this quota.
4    A user must have an Exchange Online license in order to access a shared mailbox. Shared mailboxes don’t require a separate license. However, if you want to enable In-Place Archive for a shared mailbox, you must assign an Exchange Online Plan 1 or Exchange Online Plan 2 license to the mailbox. If you want to enable In-Place Hold for a shared mailbox, you must assign an Exchange Online Plan 2 license to the mailbox.
5   Resource mailboxes don’t require a license.
6   In-Place Archive isn’t included in Exchange Online Kiosk. However, it can be purchased as an add-on through Exchange Online Archiving. For more information, please see the Exchange Online Archiving Service Description.
7   Exchange Online Kiosk users can’t access shared mailboxes.
8   This is the default mailbox size for Microsoft Exchange Server 2013 organizations. Administrators can change this value for their organization. You are limited to 100 public folder mailboxes, and the maximum total size of all public folder mailboxes is 10 TB.
9   You are limited to 50 public folder mailboxes, and the maximum total size of all public folder mailboxes is 2.5 TB.
10   In-Place Archive can only be used to archive mail for a single user or entity for which a license has been applied. Using an In-Place Archive 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.
11   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.

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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 cannot 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.

 

Feature

Office 365 Business Essentials

Office 365 Business Premium

Office 365 Enterprise E1

Office 365 Education E1

Office 365 Government E1

Office 365 Enterprise E3

Office 365 Education E3

Office 365 Government E3

Office 365 Enterprise E4

Office 365 Education E4

Office 365 Government E4

Office 365 Enterprise K1

Office 365 Government K1

Warning

49 GB

49 GB

49 GB

49 GB

49 GB

1.96 GB

Prohibit Send

49.5 GB

49.5 GB

49.5 GB

49.5 GB

49.5 GB

1.98 GB

Prohibit Send/Receive

50 GB

50 GB

50 GB

50 GB

50 GB

2 GB

 

Feature

Exchange Server 2013

Exchange Online Plan 1

Exchange Online Plan 2

Exchange Online Kiosk

Warning

1.9 GB1

49 GB

49 GB

1.96 GB

Prohibit Send

2 GB1

49.5 GB

49.5 GB

1.98 GB

Prohibit Send/Receive

2.3 GB1

50 GB

50 GB

2 GB

NoteNote:
1 This is the default value for Exchange Server 2013 organizations. Administrators can change this value for their organization.

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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 to 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.

 

Feature

Office 365 Business Essentials

Office 365 Business Premium

Office 365 Enterprise E1

Office 365 Education E1

Office 365 Government E1

Office 365 Enterprise E3

Office 365 Education E3

Office 365 Government E3

Office 365 Enterprise E4

Office 365 Education E4

Office 365 Government E4

Office 365 Enterprise K1

Office 365 Government K1

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

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

1000

1000

1000

1000

1000

1000

Warning for number of subfolders per mailbox folder

900

900

900

900

900

900

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

100,000

100,000

100,000

100,000

100,000

Not available

Maximum number of subfolders per public folder

1,000

1,000

1,000

1,000

1,000

Not available

Warning for number of subfolders per public folder

900

900

900

900

900

Not available

 

Feature

Exchange Server 2013

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

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

NoteNote:
1Microsoft recommends no more than 1,000,000 messages per mailbox folder.

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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 will not 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 Office 365 now supports larger email messages.

    NoteNote:
    Particular 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.
  • 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 is 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.

    NoteNote:
    This is the maximum file size of a single attachment. Individual client programs, including Outlook Web App, 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.

 

Feature

Office 365 Business Essentials

Office 365 Business Premium

Office 365 Enterprise E1

Office 365 Education E1

Office 365 Government E1

Office 365 Enterprise E3

Office 365 Education E3

Office 365 Government E3

Office 365 Enterprise E4

Office 365 Education E4

Office 365 Government E4

Office 365 Enterprise K1

Office 365 Government K1

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

35 MB

35 MB

35 MB

35 MB

35 MB

35 MB

Message size limit - migration

150 MB 4

150 MB 4

150 MB 4

150 MB 4

150 MB 4

150 MB 4

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

25 MB

25 MB

25 MB

25 MB

25 MB

25 MB

File attachment size limit - Outlook for Mac

35 MB

35 MB

35 MB

35 MB

35 MB

35 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

NoteNote:
1 Office 365 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 Office 365 now supports larger email messages.
2 You can send and receive up to 150 MB messages between Office 365 users (where the message never leaves the Office 365 datacenters). Messages that are routed outside of the Office 365 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 size of messages to be moved into Exchange Online are computed by Exchange Online. Versions of Exchange prior to Exchange Server 2013 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.

 

Feature

Exchange Server 2013

Exchange Online Plan 1

Exchange Online Plan 2

Exchange Online Kiosk

Message size limit - Outlook

10 MB4

150 MB1, 2

150 MB1, 2

25 MB2

Message size limit - OWA

10 MB4

112 MB1, 3

112 MB1, 3

150 MB1, 2

Message size limit - Outlook for Mac

10 MB4

35 MB

35 MB

Message size limit - migration

Not applicable

150 MB 5

150 MB 5

150 MB 5

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

25 MB

25 MB

25 MB

File attachment size limit - Outlook for Mac

35 MB4

35 MB

35 MB

35 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

NoteNote:
1 Office 365 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 Office 365 now supports larger email messages.
2 You can send and receive up to 150 MB messages between Office 365 users (where the message never leaves the Office 365 datacenters). Messages that are routed outside of the Office 365 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 2013 organizations. Administrators can change this value for their organization.
5 The size of messages to be moved into Exchange Online are computed by Exchange Online. Versions of Exchange prior to Exchange Server 2013 may report a smaller item size.

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These limits are applied to messages, senders, or recipients to combat spam and mass-mailing worms or viruses.

NoteNote:
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.
  • 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.

    NoteNote:
    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.

    NoteNote:
    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.
  • Message rate limit   Message rate limits determine how many messages a user can send within a specified period of time. This limit helps prevent overconsumption 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. For users submitting via any other mechanism, the messages are accepted, but Exchange Online will queue them at the server and throttle the rate of delivery.

 

Feature

Office 365 Business Essentials

Office 365 Business Premium

Office 365 Enterprise E1

Office 365 Education E1

Office 365 Government E1

Office 365 Enterprise E3

Office 365 Education E3

Office 365 Government E3

Office 365 Enterprise E4

Office 365 Education E4

Office 365 Government E4

Office 365 Enterprise K1

Office 365 Government K1

Recipient rate limit

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 limit

500 recipients

500 recipients

500 recipients

500 recipients

500 recipients

500 recipients

Message rate limit (SMTP client submission only)

30 messages per minute

30 messages per minute

30 messages per minute

30 messages per minute

30 messages per minute

30 messages per minute

 

Feature

Exchange Server 2013

Exchange Online Plan 1

Exchange Online Plan 2

Exchange Online Kiosk

Recipient rate limit

No limit1

10,000 recipients per day

10,000 recipients per day

10,000 recipients per day

Recipient limit

500 recipients1

500 recipients

500 recipients

500 recipients

NoteNote:
1   This is the default limit for Exchange Server 2013 organizations. Administrators can change this value for their organization.

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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.

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.

 

Feature

Office 365 Business Essentials

Office 365 Business Premium

Office 365 Enterprise E1

Office 365 Education E1

Office 365 Government E1

Office 365 Enterprise E3

Office 365 Education E3

Office 365 Government E3

Office 365 Enterprise E4

Office 365 Education E4

Office 365 Government E4

Office 365 Enterprise K1

Office 365 Government K1

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

NoteNote:
1   This is the default limit. Administrators can change this value for their organization.

 

Feature

Exchange Server 2013

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

NoteNote:
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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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). The total recipient count is determined after distribution group expansion.

 

Feature

Office 365 Business Essentials

Office 365 Business Premium

Office 365 Enterprise E1

Office 365 Education E1

Office 365 Government E1

Office 365 Enterprise E3

Office 365 Education E3

Office 365 Government E3

Office 365 Enterprise E4

Office 365 Education E4

Office 365 Government E4

Office 365 Enterprise K1

Office 365 Government K1

Maximum number of distribution group members

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 large distribution groups

2 MB

2 MB

2 MB

2 MB

2 MB

2 MB

 

Feature

Exchange Server 2013

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 message size for large distribution groups

10 MB1

2 MB

2 MB

2 MB

NoteNote:
1   This is the default limit for Exchange Server 2013 organizations. Administrators can change this value for their organization.

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The following list includes limits that apply to 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 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 by 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.

  • 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.

 

Feature

Office 365 Business Essentials

Office 365 Business Premium

Office 365 Enterprise E1

Office 365 Education E1

Office 365 Government E1

Office 365 Enterprise E3

Office 365 Education E3

Office 365 Government E3

Office 365 Enterprise E4

Office 365 Education E4

Office 365 Government E4

Office 365 Enterprise K1

Office 365 Government K1

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 (in KB) for all regular expressions used in all transport rules

20 KB

20 KB

20 KB

20 KB

20 KB

20 KB

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

 

Feature

Exchange Server 2013

Exchange Online Plan 1

Exchange Online Plan 2

Exchange Online Kiosk

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 (in KB) 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

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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. 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.

 

Feature

Office 365 Business Essentials

Office 365 Business Premium

Office 365 Enterprise E1

Office 365 Education E1

Office 365 Government E1

Office 365 Enterprise E3

Office 365 Education E3

Office 365 Government E3

Office 365 Enterprise E4

Office 365 Education E4

Office 365 Government E4

Office 365 Enterprise K1

Office 365 Government K1

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

 

Feature

Exchange Server 2013

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

NoteNote:
1   This is the default limit for Exchange Server 2013 organizations. Administrators can change this value for their organization.

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 file attachment limit   The maximum size of message file attachment that can be sent or received by an Exchange ActiveSync device.

 

Feature

Office 365 Business Essentials

Office 365 Business Premium

Office 365 Enterprise E1

Office 365 Education E1

Office 365 Government E1

Office 365 Enterprise E3

Office 365 Education E3

Office 365 Government E3

Office 365 Enterprise E4

Office 365 Education E4

Office 365 Government E4

Office 365 Enterprise K1

Office 365 Government K1

Exchange ActiveSync device limit

100

100

100

100

100

100

Exchange ActiveSync device deletion limit

20

20

20

20

20

20

Exchange ActiveSync file attachment limit

25 MB

25 MB

25 MB

25 MB

25 MB

25 MB

 

Feature

Exchange Server 2013

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

Exchange ActiveSync file attachment limit

25 MB

25 MB

25 MB

25 MB

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