How to Separate Email Recipients With Commas in Outlook

Commas as email address separators aren't the default in Outlook

One black comma in many red commas

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In most email programs, it's common practice to separate names of email recipients with commas. However, in Outlook, the semicolon is used to separate email recipients. If you'd rather use a comma, change the Outlook settings.

Instructions in this article apply to Outlook 2019, 2016, 2013, 2010; Outlook for Office 365; and Outlook Online.

Why Comma Separators Don't Work in Outlook

If commas are used to separate recipients in Outlook, a "name could not be resolved" message appears. This means that Outlook doesn't understand the syntax used when typing the recipient addresses.

Outlook thinks a comma separates the last name from a first name. If you enter she@example.com, Mark in Outlook, Outlook interprets that recipient as Mark she@example.com.

Make Outlook Allow Commas to Separate Multiple Email Recipients

To have Outlook see commas when separating multiple email recipients:

  1. Go to the File tab and select Options.

    Screenshot of opening Options in Outlook
  2. Select the Mail category.

    Screenshot of Send messages in Outlook
  3. In the Send messages section, select the Commas can be used to separate multiple message recipients check box.

    Screenshot of enabling commas for recipients in Outlook
  4. Select OK.

Allow Commas to Separate Multiple Email Recipients in Outlook.com

Outlook.com automatically recognizes a comma between email addresses as the separator between contacts.

  1. In the To text box, enter an email address, then type a comma.

    Screenshot of using a comma after recipient in Outlook.com
  2. Outlook.com searches for that contact in your contact list. If it finds it, it inserts the contact. If it doesn't find it, it accepts the email address you typed and places a box around it.

    Screenshot of adding recipients using commas in Outlook.com
  3. When you finish adding recipient emails separated by commas, compose the message and press Send to finish.