What are the size limits for Office 365?

There are lots of different limits on the use of the Office 365 services. These are set at a level that reasonable use of the service will not encounter any of these limits.

Mailbox limits

Mailbox limits
User mailbox storage limit The maximum amount of all email which can be stored in the users mailbox (including attachments)  50 GB
Shared mailbox storage limit The maximum amount of all email which can be stored in the shared mailbox (including attachments)   10 GB
Prohibit send capacity alert 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.  49.5 GB

 Message limits

Message limits
Message size limit The maximum total size of an email message. The total size includes the message header, the message body and any file attachments.  25 MB
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 a message.  250 attachments
Subject length limit The maximum number of text characters allowed in the subject line of an email message.  255 characters

Recipient limits 

Recipient limits
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 apply to all outbound and internal messages.  10,000 recipients a day

Recipient limit The maximum number of message recipients allowed in the To:, Cc: and Bcc: fields. A group is counted as a single recipient.

If you are using Office 365 you will not be able to send am email to more than 100 recipients in a single email, but can be increased by contacting the itservicedesk@leeds.ac.uk

 100 recipients
Message rate limit The maximum number of e-mail messages that can be sent from a single e-mail client per minute. The client is identified by the user account.  30 messages per minute

Retention limits

Retention limits
Deleted Items folder retention period The maximum number of days that items can remain in the Deleted Items folder before they are automatically removed.  30 days
Retention period for items removed from the Deleted Items folder The maximum number of days that items removed from the Deleted Items folder are retained before they are permanently deleted.  14 days
Junk Email folder retention period The maximum number of days that items can remain in the Junk Email folder before they are automatically removed.  30 days

Find out more information regarding all limits when using Office365 .