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Email for Faculty and Staff

Email for Faculty and Staff

Office 365: Email and calendar for faculty, staff, and graduate students

Office 365 is the university's email system for faculty, staff, and graduate and professional students. It is a cloud-based service from Microsoft that manages email, calendars, task lists, and address books.

Undergraduates and alumni use Google Workspace for Students, formerly known as G Suite.

Features of Your Office 365 Account

  • Mailbox size: 100 GB for faculty and staff; 50 GB for alumni, students, and those with temporary, sponsored, or affiliate NetIDs.
  • Email software: Outlook or Outlook on the web recommended. See our Choose an Email Client article.
  • Mobile devices: works with Android, iPhone, Windows Phone, and other devices that support ActiveSync. See how to get connected with your iOS device or how to get connected with your Android or other device.
  • Outlook on the web:
  • Deleted Items retention: Messages remain in your Deleted Items folder for 30 days and are then automatically deleted.
    (Explanation: When you click Delete on a message, or when you respond to a calendar invitation, it is automatically placed in your Deleted Items folder. Thirty days later, the message will be removed from your Deleted Items folder. If you're likely to want the message longer than 30 days, you should keep it in your Inbox or another folder instead of clicking Delete.)
  • Message size limit: 25 MB (total size including attachments). The limit applies for both outgoing and incoming messages. See our Attachments Not Getting Through article for details.
If you need to send files larger than 25 MB, use Cornell Box (cloud storage that you can share) or Cornell Secure File Transfer instead (for sizes up to 5 GB).
  • Maximum number of attachments on a single message: 250

Resigning, retiring, or otherwise leaving Cornell? Find out what changes to expect for your Cornell email account.

Limits on Sending Very Large Mailings

Office 365 includes some security defenses that limit the ability of an individual to send huge numbers of messages in a short amount of time. If you have legitimate large mailings to do, please understand these limits and the alternatives you have for delivering your messages.

Maximum number of addresses allowed in the To:, Cc:, and Bcc: fields (combined): 500 per message

Maximum number of messages that can be sent from your email client per minute: 30

Maximum number of recipients who can receive messages sent from your account (or a Resource Account) in a 24-hour period: 10,000 (and no more than 5,000 can be to external addresses (that is, addresses other than


  • The 24-hour period is a rolling window: for example, if you send messages to 2,000 recipients at 8:30am, then messages to 5,000 recipients at 12 noon, then messages to 2,000 recipients at 2:30pm, and messages to 1,000 recipients at 4pm, you won't be able to send any more messages until 8:30am the next day.
  • If you try to send a message after exceeding the limit, you will either see an immediate error about the recipient limit, or the message will be returned to you with an error. Save the message to your Drafts folder and try again later.
  • A message will only be delivered if it can be delivered to all the recipients without going over the 10,000-limit. For example, if you've already sent messages to 9,900 recipients, and you attempt to send one message to 150 recipients, it will not be delivered because it would be 50 recipients over your limit for the 24-hour period.

Alternatives for Very Large Mailings

Create and use one or more e-lists: a good choice if you'll email these same individuals many times and they're not all at Cornell.

Request and use a CornellAD mail-enabled group: a good choice if these individuals are all at Cornell and you'll email these same individuals many times (a mail-enabled CornellAD group is only counted as one recipient).

Use bulkmail: a good choice if this is the only time you'll email this particular group of individuals.

Third-party senders: Thinking about using an external vendor to distribute official Cornell messages? Please read our article about using third-party senders.

A Few Additional Account Limits

Maximum messages per folder: 1,000,000

Maximum subfolders per folder: 1,000

Maximum folder hierarchy depth: 300

Maximum subject length: 255 characters

Maximum number of attachments to one message: 250

Service Details

Office 365, a cloud-based service from Microsoft, provides email and calendar services for faculty, staff, retirees, graduate and professional students, and student employees. 


No Fee

Regulated Data:

Not applicable or information not available.

Support Contact:

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