Email Sending Limits for SCSU Office 365 Accounts

Introduction

Reducing email sending limits is a preventative measure designed to minimize the impact of compromised accounts and protect other users from potential harm.

Instructions

Email Sending Limits and Recommendations

Frequently Asked Questions

Q: How many emails can I send as an employee, student, or alumni?
Q: What are the sending limits for distribution lists?

Sending Limits

Students and Alumni (Office 365 Shared Tenant)

• External hourly limit: 100 recipients
• Internal hourly limit: 500 recipients
• Daily limit: 1,500 recipients

Employees

• Recipient rate limit: 10,000 recipients per day
• Customizable recipient limit: Up to 1,000 recipients
• Recipient address limit: 400 addresses per message
• Message rate limit: 30 messages per minute

Distribution Lists

• Daily limit: 10,000 recipients

Recommendations if You Are Blocked from Sending

1. Use a Shared Mailbox
   Shared mailboxes can be used for mass messaging. While sending limits still apply, using a shared mailbox helps protect the individual sender’s mailbox from being blocked. If one does not exist, it should be created.

2. Choose Between Distribution Group or ListServ
   The choice depends on whether external recipients are involved.

   • A contact group in an individual mailbox is not the same as a ListServ or distribution group.
   • Contact groups count each recipient individually, increasing the risk of being blocked.
   • A distribution group or ListServ counts as one recipient and is easier to manage.
   • Proper setup takes about five minutes and requires minimal ongoing maintenance.

3. Schedule Mail Delivery
   If the recipient list changes frequently, consider scheduling emails in batches.

   • Limit each batch to fewer than 50 recipients.
   • Schedule no more than one delivery per hour.
   • This approach helps avoid Microsoft’s sending limits and ensures normal mail flow.
   • Office Support KB on how to delay or schedule sending