How to mail merge in Outlook

Outlook can send a personal email to everyone on a list, with their own name in it. You write it in Word, pick an Excel list, and classic Outlook sends one email per person. New Outlook works differently, and attachments need a workaround.

By David Ray · Updated October 30, 2026 · 5 min read · How we research

Which Outlook do you have?

Microsoft now has two Outlook apps for Windows, and mail merge works differently in each:

• Classic Outlook has a File tab at the top left and is part of Microsoft 365 or Office. Word's mail merge sends through this one.
• New Outlook has a New Outlook or Try the new Outlook toggle at the top right, and looks like Outlook on the web. It has no File tab in the same place.

If you have new Outlook, you can usually switch back by turning off the New Outlook toggle at the top right. Work accounts may have this controlled by IT.

Mail merge from Word to Outlook (classic)

You need your list in Excel (or a CSV), Word, and classic Outlook signed in to the account you want to send from. Make classic Outlook your default email app.

1. Open Word and go to Mailings › Start Mail Merge › E-mail Messages.
2. Click Select Recipients › Use an Existing List, open your Excel file, pick the sheet, and click OK. The sheet needs a column of email addresses.
3. Type your email in the Word page. Add personal details with Greeting Line (for "Dear Jane,") or Insert Merge Field (for any column, like «Company»).
4. Click Preview Results and use the arrows to check a few people.
5. Click Finish & Merge › Send E-mail Messages.
6. Set To to your email column and type the Subject line. Choose HTML for formatted text or Plain text. Under Send records, test first with Current record.
7. Click OK. Outlook sends one separate email to each person. Each person sees only their own address.

Can't do the spreadsheet part? Our step-by-step guide on mail merge from Excel to Word covers setting up the sheet, labels and letters, and fixing dates and ZIP codes.

Start from your Outlook contacts

In classic Outlook you can also merge straight from your contacts, without Excel:

1. In classic Outlook, open People (or press Ctrl+3).
2. Select the contacts you want, or a contact folder.
3. On the Home tab, click Mail Merge. If you don't see it, look under the ... (more) menu.
4. Under Merge options, set Document type to Form Letters and Merge to to E-mail. Type the subject in Message subject line and click OK.
5. Word opens. Write the message, add fields, then click Finish & Merge › Send E-mail Messages.

Mail merge in new Outlook

Here is where it gets confusing. Microsoft's own feature comparison lists mail merge as only "Partially Available" in new Outlook. In practice:

• Word's Send E-mail Messages doesn't send through new Outlook. Microsoft says Word needs classic Outlook to read your contacts and send merged emails.
• New Outlook has its own basic mail merge. In a new email, click the arrow next to Send and choose Start mail merge (it may also be on the Options tab). It sends a separate copy to each recipient, so nobody sees the other addresses.
• But it isn't personal. Microsoft says this option doesn't insert personal contact fields, so everyone gets the same text. Write a greeting that works for everyone, like "Hi there". Microsoft has announced personal fields for it on its roadmap; if you see them when you start a merge, your account has them.

If you're stuck on new Outlook today, you have two options: switch back to classic Outlook for the merge, or use a mail merge add-on from the Outlook add-ins store.

Can you add attachments?

Not with Word and Outlook's built-in mail merge. Microsoft's help page says it plainly: you can't add attachments, but you can include links. Your options:

• Link to the file instead. Upload it to OneDrive, Google Drive or Dropbox and paste a share link. This is also kinder to inboxes.
• Use an add-on. Several paid Outlook add-ons send merges with attachments, including a different file for each person. Check the reviews and what access it asks for before you install one.
• Send a few by hand. For 10 or 20 people, it is quicker to send each email yourself and attach the file.

Sending limits

Outlook sends each merged email as a normal email from your account, so your account's limits apply:

A merge to a list full of old or mistyped addresses bounces a lot, and many bounces in one day can get your account limited. Check the list before you send.

Sending the same email one at a time instead? An Outlook email template may be all you need.

If it doesn’t send

• Send E-mail Messages is greyed out: start the merge with E-mail Messages, not Letters, and make sure classic Outlook is installed and set up.
• Nothing happens after OK: you are probably on new Outlook. Switch to classic Outlook, open it once, then run the merge again.
• Emails are stuck in the Outbox: classic Outlook is offline or still sending. Leave it open until the Outbox is empty.
• An error about the "default mail client" or "MAPI": set classic Outlook as your default email app in Windows Settings › Apps › Default apps, and make sure Word and Outlook are both from the same Microsoft 365 or Office install.

Questions people ask

How do I mail merge in Outlook?

Use Word: Mailings, Start Mail Merge, E-mail Messages. Pick your Excel list with Select Recipients, add fields, then click Finish & Merge, Send E-mail Messages. Classic Outlook sends one email to each person.

Does mail merge work in new Outlook?

Only partly. Word's email merge does not send through new Outlook. New Outlook has a basic Start mail merge option that sends a separate copy to each person, but without personal fields like their name.

Can I add an attachment to a mail merge in Outlook?

Not with the built-in mail merge. Put a link to the file in the email, or use a paid Outlook add-on that supports attachments.

Will recipients see each other's addresses?

No. A mail merge sends a separate email to each person, so they only see their own address.

How many emails can I mail merge in Outlook?

Your account's limit applies. Outlook.com with Microsoft 365 allows 5,000 recipients a day; free accounts get less. Work accounts follow your organization's limits.