by Didem Kiran · Last updated: 2026-09-02

Google Sheets Mail Merge Add-ons Compared: YAMM vs Mailmeteor vs GMass

To mail merge from Google Sheets, you install an add-on, point it at your spreadsheet, and draft one Gmail message that uses your column names as merge fields. For a single send, YAMM, Mailmeteor, and GMass all do the job. Pick by sending limit, tracking, and follow-ups. If you add people one at a time and reuse their details, move the sheet into a contact list instead.

That last line is the fork in the road most guides skip. A mail merge from a Google Sheet is perfect for a one-off blast: a launch announcement, a seasonal note, an event invite. The moment your list becomes a living thing that grows every week, the spreadsheet turns into busywork. This guide covers both: how each add-on works, and when to stop merging from a sheet altogether.

New here? Start with our primer on Email Platform Comparisons for the fundamentals, then come back to this guide.

Quick context: Mailsoftly offers transparent pricing, free hands-on migration, and human support. 500 contacts and 2,000 emails per month with your Gmail, Outlook, Google Workspace or Microsoft 365 account, no credit card.
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How does a Google Sheets mail merge work?

A Google Sheets mail merge turns spreadsheet columns into merge fields inside a single Gmail draft, then sends one personalized copy per row. You write the email once with placeholders like the recipient’s first name, and the add-on swaps in each person’s data as it sends. Here is the flow, using a fictional Bay Area local directory publisher emailing 80 small advertisers about a new listing package.

1. Build the sheet. One row per recipient. Columns become fields: Email, First Name, Business Name, Renewal Month.
2. Install the add-on. YAMM and Mailmeteor run from inside Google Sheets; GMass runs from inside Gmail and reads the sheet.
3. Draft in Gmail. Write the message and drop in placeholders, such as Hi {{First Name}}, your {{Business Name}} listing renews in {{Renewal Month}}.
4. Map and preview. The add-on matches placeholders to columns and shows a test row so you catch blanks before sending.
5. Send and track. Each recipient gets a clean, individual email, and the add-on logs opens or replies back to the sheet.

If you only want the built-in method with no third-party tool, our walkthrough on how to run a mail merge in Gmail covers the native multi-send approach and where it stops.

Read enough? Try Mailsoftly free with 500 contacts and 2,000 emails per month with your Gmail, Outlook, Google Workspace or Microsoft 365 account, no credit card.Start free with Mailsoftly →

YAMM (Yet Another Mail Merge): what is it and who is it for?

YAMM is a Google Workspace add-on that runs inside Google Sheets and sends through your Gmail draft. It is the oldest and most familiar name in this space, which is why so many teams reach for it first.

• Setup: Install from the Workspace Marketplace, open your sheet, write a Gmail draft, and hit send from the YAMM menu.
• Personalization: Column headers become merge fields you reference in the draft, including subject line personalization.
• Tracking: Open and click status writes back into a column on the sheet so you can eyeball who engaged.
• Who it fits: Someone who lives in Google Sheets and wants the shortest path from spreadsheet to a personalized blast.

One honest limit: YAMM is built around the send, not the relationship. There is no per-contact profile that carries forward, so next month you start again from a spreadsheet. Check the current free daily cap and paid tiers on the YAMM pricing page before you commit to a large list.

Mailmeteor: what is it and who is it for?

Mailmeteor is a Google Sheets add-on and web app focused on a clean, privacy-forward merge experience. It leans on a simple editor and clear previews, which makes it approachable for non-technical senders.

• Setup: Install the add-on, connect your sheet, and compose either in the Mailmeteor editor or a Gmail draft.
• Personalization: Merge fields pull from your columns, with a live preview per recipient so blanks are visible before send.
• Tracking: Opens and clicks are reported, and results tie back to your recipient rows.
• Who it fits: A solo sender or small team that wants the least fiddly setup and a tidy preview step.

One honest limit: like YAMM, Mailmeteor is a sending layer on your spreadsheet. It does not become a database of contacts with history, so repeat, evolving campaigns still mean maintaining the sheet by hand. Confirm free-tier daily limits and pricing on Mailmeteor’s own pricing page at the time you sign up.

GMass: what is it and who is it for?

GMass is a Chrome extension that lives inside Gmail rather than Sheets. You connect a Google Sheet as the source, but the whole workflow, composing, scheduling, and automated follow-ups, happens in the Gmail interface. It skews toward cold outreach and sales-style sequences.

• Setup: Install the Chrome extension, connect a sheet as the list, and compose in Gmail’s normal window.
• Personalization: Merge fields map to sheet columns, with fallback text options for empty cells.
• Tracking: Detailed open, click, and reply reporting, built for outreach at volume.
• Who it fits: Sales and outreach senders who want staged follow-ups and heavier reporting from Gmail.

One honest limit: GMass is powerful, and that power invites volume sending that Gmail was not built for, which raises deliverability and reputation risk fast. Already on GMass and want a different setup? See our roundup of GMass alternatives. Verify GMass pricing and free-trial caps on their official pricing page before you scale.

YAMM vs Mailmeteor vs GMass: how do they compare?

The short version: YAMM and Mailmeteor are Sheets-first add-ons for personalized blasts, GMass is a Gmail-first extension built for outreach sequences. The table below covers what is stable and verifiable. For daily limits, free-tier size, and current prices, check each vendor’s official pricing page at write time, since those change often.

Notice the difference in the last row. With the three add-ons the personalization data lives in a spreadsheet you rebuild each time. With a contact list the fields live on the person, which is the distinction that matters once you send more than once.

What are the sending limits for a Google Sheets mail merge?

Every Google Sheets mail merge is capped by your Gmail account, not by the add-on. Because YAMM, Mailmeteor, and GMass all send through Gmail, they inherit Google’s daily recipient limits. A personal Gmail account gets a lower daily cap than a paid Google Workspace account, and going over means the rest of your merge simply does not send that day.

Add-ons may layer their own per-plan sending limits on top of Google’s, so your real ceiling is whichever number is lower. Before a big send, confirm both your account tier and the add-on plan against Gmail sending limits in Google Workspace, which lists the current daily figures directly from Google.

The practical takeaway: a Sheets mail merge is fine for a few dozen to a few hundred recipients. Past that, you are fighting daily caps and deliverability, and a dedicated sending setup with your own authenticated domain becomes the safer route.

When does the Google Sheet stop working?

The sheet stops working the moment your list becomes ongoing rather than one-time. A mail merge from Google Sheets assumes a fixed list you export, blast, and forget. Three signals tell you that assumption has broken.

• New contacts every week. A real estate agent who adds two or three new leads after every open house ends up copying rows, deduping, and re-checking the same spreadsheet forever.
• Per-person details scattered around. When renewal dates, package tiers, and notes live in different tabs or files, one merge means stitching data together by hand each time.
• No history per contact. The sheet cannot tell you what a given person already received, so you risk repeats, gaps, and awkward duplicate sends.

A wedding photographer booking couples across a season hits all three within a month. At that point the spreadsheet is not saving time, it is quietly costing it. The fix is to make the data live on the contact, not the row.

How do you move a sheet into Mailsoftly?

You import the sheet once, map each column to a custom field, and from then on you add people one at a time instead of rebuilding a spreadsheet. Mailsoftly supports custom contact fields as Text, Number, Date, and Single or Multiple choice, and each field lives on the individual contact profile where it is filled in per person.

Personalization uses merge tags like {(first_name)} and {(Field Name)}, and the Personalize button lists your contact fields and custom fields as insertable chips so you never mistype a placeholder. Empty fields will not break a sentence: fallback text plus IF, PREFIX, and SUFFIX blocks let a tag read cleanly whether or not the value is present. So Renews in {(Renewal Month)} can quietly disappear for the one contact who has no date on file.

Adding people is a single action. You can add one contact by hand and enroll them straight into an automation or sequence, no CSV round trip needed. Sending goes through a connected Google Workspace, personal Gmail, or Microsoft 365 mailbox over OAuth, so there is no DNS work and replies land in your own inbox, with a daily recipient cap on that lane and a lower cap on personal Gmail. For larger sends you switch to your own authenticated domain. Prefer not to do the import yourself? Mailsoftly offers Import your sheet free with a person who maps the columns for you.

On price, the free plan (as of 2026-09-07) covers 500 contacts and 2,000 emails per month with your Gmail, Outlook, Google Workspace or Microsoft 365 account with no credit card, and paid plans start at 15 dollars per month billed annually for 1,000 contacts. You can compare tiers on the Mailsoftly pricing page.

For the broader picture on this topic, see our complete Email Platform Comparisons guide, which covers strategy, fundamentals, and advanced playbooks.

Frequently Asked Questions

Is there a free mail merge for Google Sheets?

Yes. YAMM, Mailmeteor, and GMass each offer a free tier with a daily send cap, and Gmail’s own multi-send is free for small lists. Check the current free daily limit on each vendor’s pricing page, since those numbers change. If you send repeatedly, Mailsoftly’s free plan covers 500 contacts and 2,000 emails per month with your Gmail, Outlook, Google Workspace or Microsoft 365 account with no card.

How many emails can I send with a Google Sheets mail merge?

Your ceiling is set by Gmail, not the add-on. A personal Gmail account has a lower daily recipient cap than a paid Google Workspace account, and the add-on may cap you further on its free tier. The lower of the two numbers wins. See Google’s official Workspace help page for the current daily figures before a large send.

Can I add attachments to a mail merge?

Yes, in most cases. The three add-ons support attaching files to a merge, though large or per-recipient attachments can vary by plan, so confirm on the vendor page. A cleaner approach for repeat sends is to host the file and link to it, which keeps message size down and improves deliverability.

Does mail merge work with Google Workspace?

Yes. All three add-ons work with Google Workspace, and a paid Workspace account gives you a higher daily sending cap than a personal Gmail account. Mailsoftly also connects to a Workspace mailbox over OAuth, so you send from your own address, replies return to your inbox, and no DNS setup is required.

Ready to switch?Start free with Mailsoftly →
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Didem Kiran

Content Strategist at Mailsoftly

Didem is a Business Development Specialist at Mailsoftly, based in San Ramon, California. She has focused on building partnerships and helping businesses grow with AI-powered email and marketing automation.