As an administrator, you can limit the number of recipients for email messages sent by people in your organization. For example, a school district may want to limit the number of recipients that students can send messages to. Limiting email recipients prevents people in your organization from sending mass emails, and helps your organization comply with our bulk email best practices .

To set up message recipient limits, add a compliance rule in the sender’s organizational unit. For detailed information about compliance rules, visit Set up rules for content compliance .

Important:Compliance rules don’t override other email management settings. For example, compliance rules don’t override authorized domains and addresses .

Limit message recipients with a compliance rule

Follow the steps in this section for each organizational unit where you want to limit the recipients for outgoing messages.

When someone tries to send a message with more recipients than allowed, the message isn't delivered to recipients, and the sender gets a bounce message.

1. Sign in to your Google Admin console .

   Sign in using your administrator account (does not end in @gmail.com).

2. In the Admin console, go to Menu  Apps Google Workspace Gmail Compliance.
3. On the left, select the organizational unit where you want to limit message recipients. 
4. Scroll to the Content Compliancesection, then click Configureor Add another rule.

5. In the Add settingbox, take these steps:

   Setting options

   What to do

   Content compliance

   Enter a descriptive name for the setting. If you don't enter a name, you can't save your setting.

   Email messages to affect

   Check the  Outbound and Internal - Sending boxes.

   A domain is internal if it is a verified workspace domain, or a subdomain or parent domain of a verified workspace domain.

   Add expressions that describe the content you want to search for in each message

   1. Click the menuand select If ALL of the following match the message.
   2. Click Add. A second Add settingbox opens.
   3. At the top of the Add settingbox, select Advanced content match.
   4. Under Location, select Recipients header.
   5. Under Match type, select Matches regex.
   6. Under Regexp, enter: [@].  Learn more about regular expressions (regex) .
   7. Under Minimum match count,enter a number to specify the maximum number of recipients for messages. Add 1 to the maximum number of recipients, and enter that number. For example, to limit message recipients to 10, enter 11.
   8. At the bottom of the Add settingbox, click Save.

   If the above expressions match, do the following

   1. Click the menuand select  Reject message. When a user in your organization tries to send a message with more than the allowed number of recipients, Gmail blocks the message from being sent.
   2. (Optional) Enter a custom rejection notice that appears in bounce emails to the message sender.
6. At the bottom of the Add settingbox, click Save.
7. Check that your new compliance rule appears in the Content compliance table.

Changes can take up to 24 hours but typically happen more quickly.  Learn more

Related information

• Get started with Postmaster tools , to track data about large volumes of outgoing email 
• Best practices for faster rules testing
• Block emails between specific user groups