Mail merge lets you send one email template to a list of people, automatically filling in each person's name, address, or other details so every message feels personal

Mail merge is a feature in email and word processing programs that takes a single template — a letter or email you write once — and automatically customizes it for each person on a list. Instead of typing "Dear Sarah" in one email, "Dear Marcus" in another, and so on, you write "Dear [Name]" once, connect it to a spreadsheet of names, and the program fills in each person's details automatically.

The result is dozens or hundreds of personalized messages sent in minutes, with each recipient seeing their own name and information in the body of the email. This is useful for anything from job applications to landlord notices to customer outreach — any situation where you need the same message to go to many people, but you want each one to feel like it was written for them.

Key Takeaways

  • Mail merge takes a template with placeholder fields like [Name] or [Address] and fills them in automatically from a spreadsheet or contact list.
  • You need two things to use mail merge: a template document (usually in Word or Gmail) and a data source (usually a spreadsheet with one row per person).
  • Mail merge works in Microsoft Word, Google Docs, Gmail, and many other programs, though the exact steps differ slightly between them.
  • The most common mistake is forgetting to save your data source as a .csv file or leaving blank rows in your spreadsheet, which causes the merge to fail or skip people.

How mail merge works in practice

The process has three steps. First, you create a template — a letter, email, or document with placeholder fields where personal details should go. In Microsoft Word, these placeholders look like <<FirstName>> or <<Address>>. In Gmail, they look like [FirstName] or [Address]. You write the rest of the message normally around these placeholders.

Second, you prepare a data source — usually a spreadsheet with one row per person and one column per piece of information. The first row should be headers: Name, Email, Address, Company, and so on. Each row below contains one person's details. This spreadsheet needs to be saved as a .csv file (comma-separated values) or kept in Google Sheets if you are using Gmail.

Third, you tell the program to merge them. The program reads each row of your spreadsheet, fills in the placeholders in your template with that row's data, and creates one message per person. You then send them all at once or review them one by one before sending.

Mail merge in Microsoft Word

In Word, mail merge is called Mailings and lives in the top menu. You start with a blank document or an existing letter, then go to Mailings > Start Mail Merge > Letters. Word then walks you through selecting your data source (the spreadsheet), inserting the placeholder fields where you want them, and previewing the results.

The trickiest part is getting the data source right. Your spreadsheet must have headers in the first row — Name, Email, Address, whatever you need. Save it as a .csv file or keep it in Excel format. Word will ask you to select the file, then show you a list of the fields it found. You then click in your document where you want each field to appear and insert it.

After you insert all the fields, use Mailings > Preview Results to see what the finished messages will look like. If something is wrong — a name is misspelled, a field is in the wrong place, or a row is blank — go back and fix the template or the spreadsheet, then preview again. When everything looks right, go to Mailings > Finish & Merge and choose whether to send emails, print letters, or save the merged documents as individual files.

Mail merge in Gmail

Gmail does not have a built-in mail merge feature, but you can use a free add-on called Mail Merge by Yet Another Mail Merge (search for it in the Gmail add-ons store). The process is similar: you write a template email with placeholders like [FirstName] or [Company], then upload a Google Sheet with your contact list.

The add-on reads your spreadsheet and creates one email per row, filling in the placeholders automatically. You can preview each email before sending, and the add-on sends them one at a time so Gmail does not flag them as spam. This is slower than Word's mail merge — it may take several minutes to send 100 emails — but it works directly from Gmail without needing to export anything.

Common mistakes that break mail merge

The most frequent problem is saving the data source in the wrong format. Word needs a .csv file or an Excel file, not a Google Sheet (unless you tell Word to open Google Sheets directly). Gmail's add-on needs a Google Sheet, not a .csv file. Check your program's instructions before you save.

The second mistake is leaving blank rows or columns in your spreadsheet. If row 5 is empty, the mail merge will either skip it or create a message with blank fields. Delete any empty rows before you start. The third mistake is misspelling the placeholder field names. If your spreadsheet header says "FirstName" but your template says "First_Name", the program will not recognize them as the same field and will leave the placeholder blank in the finished message.

A fourth mistake is forgetting to update the data source after you have already started the merge. If you add new people to your spreadsheet after you have begun, you will need to start the merge over from the beginning — the program does not automatically pick up new rows.

When to use mail merge instead of just sending individual emails

Mail merge saves time when you are sending the same message to more than about five people. Below that, typing individual emails is often faster than setting up the merge. Above that, the time you save grows quickly — sending 50 personalized emails by hand takes an hour or more, while mail merge does it in minutes.

Mail merge is also useful when you need a record of what you sent. Word can save each merged email as a separate document, so you have a file for each person. This is helpful for formal notices, job applications, or anything you might need to refer back to later. Gmail's add-on keeps a log of which emails were sent and when.

Alternatives if mail merge does not work for you

If you do not want to set up mail merge, some email services offer simpler options. Many email marketing platforms like Mailchimp or Constant Contact have built-in personalization that works without needing a separate data source — you paste your contact list directly into the platform and it handles the rest. These are usually free for small lists (under 500 contacts) but charge a monthly fee for larger ones.

Another option is to use a template in your email program and manually fill in names as you go. This is slower but requires no setup. Some people also use keyboard shortcuts or text expansion tools (like TextExpander or AutoHotkey) to speed up typing the same phrases over and over, though this is not true mail merge.

Frequently Asked Questions

Can I use mail merge to send emails from my personal email account?

Yes, but it depends on your email provider. Gmail requires the Yet Another Mail Merge add-on. Outlook has a built-in mail merge feature. Yahoo and other providers do not have native mail merge, so you would need to use a third-party tool or send from Word instead.

What happens if someone's name or email is missing from my spreadsheet?

If a name is missing, the placeholder will be blank in that message — the recipient will see "Dear ," for example. If an email address is missing, most programs will skip that row entirely and not send a message. Always check your spreadsheet for blanks before you start the merge.

Can I send mail merge emails at different times instead of all at once?

Word does not have a scheduling feature, so you have to send all merged emails when ready or save them as drafts and send them manually later. Gmail's add-on also sends when ready. If you need to schedule emails, use an email marketing platform like Mailchimp, which lets you set a send time.

Is mail merge considered spam by email providers?

No, as long as you are sending to people who expect to hear from you. Spam filters look at the content of the email and the sender's reputation, not whether it was created with mail merge. However, sending hundreds of emails in a few minutes can trigger rate limits on some email accounts, so space them out if possible.

Can I use mail merge with attachments?

Word's mail merge can include the same attachment in every message, but it cannot attach different files to different people based on your spreadsheet. Gmail's add-on has the same limitation. If you need different attachments for different people, you will have to send those manually or use a more advanced email automation tool.