Limits for Office 365

There are limits imposed for Office 365 packages. This page will let you know what those limits are.

NOTE: This applies ONLY to Office 365. If you have Linux or Windows Shared Hosting, we have a list of email sending limits. You can find those here.

• Message Size — 25 MB per message, includes message header, body, and attachments
• Message Subject Length — 255 characters
• Message Rate (Incoming & Outgoing) — 30 messages per minute, 10,000 messages per 24 hours
• Recipients — 500 recipients per message
• Shared Contacts — 1000 shared contacts
• Attachment Size — 125 attachments per message, not exceeding the 25 MB message size limit

  Note: OWA has a maximum individual file attachment size of 10 MB.

• Distribution Group Members — 100,000 members
• ActiveSync Devices — 10 devices per mailbox
• Password — 8 characters minimum and 16 characters maximum
• Aliases — We recommend less than 200 aliases to ensure optimal performance, but there is no limit
• Messages per mailbox folder — 1 million messages
• Messages per folder in the Recoverable Items folder — 3 million messages
• Subfolders per mailbox folder — 1,000 folders
• Folder hierarchy depth — 300 levels
• Public folders — 100,000 folders
• Folders per public folder — 1,000 folders
• Rules — 300 rules

Additional Support

As always, should you require more assistance in relation to this issue, please contact our Helpdesk explaining your issue - and what you have done to this point, and we will be happy to assist you further.

Please see our full contact information, on our main website: Contact Us.

Alternatively, email help@blacknight.com for assistance.