How to Check if Your Emails Are Going to Spam (Free Tests)

No single free tool tells you whether one specific email you already sent landed in spam — once it's delivered, only the recipient's inbox knows that. What you can test for free, before and after you send, are three different things: a spam score for one message and your sending setup, where a real copy actually lands across inboxes you control, and how Gmail and Yahoo see your whole domain over time. Run the first before a campaign, the second after any change to your setup, and watch the third continuously once you're sending real volume.

What's the difference between a spam score and an inbox placement test?

A spam score, like the one Mail-Tester gives you, grades a single message against spam-filter rules before anyone real sees it — a prediction, not a result. An inbox placement test actually sends your email to mailboxes you control and reports which folder each one landed in, which is closer to what your real recipients experience.

Mail-Tester runs your message through SpamAssassin, an open-source spam filter, with the scale flipped so a higher number is better (mail-tester.com/faq). It checks your message and sending server, not the specific recipient's spam filter, Gmail's or Yahoo's own rules, or your sender reputation history. A 10/10 score is a good sign, but Mail-Tester itself says a perfect score doesn't guarantee inbox placement, because individual filters and the recipient's own preferences still apply.

How do you run a free spam-score test?

1. Open mail-tester.com and copy the random address it generates for you.
2. Send the actual email you're about to send to a real list — not a generic placeholder — to that address, from the real account or tool you'll use.
3. Go back to the page and click to check your score.
4. Read the report: it breaks down what's configured correctly and what isn't.
5. Run it again after you fix anything. The free plan gives you 3 tests in a rolling 24 hours, and a result stays visible for 7 days.

Do this before any campaign that changes your sending domain, your email tool, or your message template — not just once when you set everything up.

How do you run a free inbox placement test with your own inboxes?

Create or use a small set of inboxes you already own — a Gmail account, an Outlook or Microsoft 365 account, a Yahoo account, and one inbox on your own sending domain are enough to start. Send your real email to all of them at once, then check where each one landed.

• Gmail: check Primary, Promotions and Spam, not just the inbox tab you expect.
• Outlook or Microsoft 365: check Focused and Other, plus Junk Email.
• Yahoo: check Inbox and Spam.

This is exactly what a seed-list test is, and it's free as long as you're willing to check each inbox by hand. GlockApps automates the checking part: its free plan includes 2 spam test credits after signup, though its pricing page doesn't say how often those credits renew (checked November 2026).

If you want this running automatically rather than one-off, Mail Mantis — a free, open-source tool from the maker of Larvabot — does the same seed-list check on a schedule. You connect inboxes you own (Gmail, Outlook, Yahoo, iCloud or any IMAP account), it sends ordinary emails between them, and for each one it reports whether it landed in Primary, Promotions or Spam on Gmail, Focused or Other on Outlook, or in the spam folder it reads directly. It's built for warming up and monitoring your own domain, not for outreach campaigns, and it's upfront that no tool can guarantee inbox placement — authentication and real engagement still matter more.

Larvabot sends the emails you approve through Brevo's free tier in small batches by default, 1–2 a day per campaign, which already keeps a brand-new domain from spiking volume right when you're trying to test it.

How do you check your domain's reputation with Google and Yahoo?

Run a placement test on one message; check Postmaster Tools and Sender Hub for your whole domain's standing over time. Both are free, but neither shows anything until you've sent enough real volume for them to measure.

Google Postmaster Tools tracks your domain's spam rate, authentication pass rate and delivery errors with Gmail specifically. Google's own sender guidelines set two thresholds: keep your Postmaster Tools spam rate under 0.10%, and never let it reach 0.30% or higher, the harder limit that applies to anyone sending 5,000 or more messages a day to Gmail addresses (support.google.com/mail/answer/81126). If your dashboards show "No data to display," it usually means your Gmail volume is too low to register yet, not that something's broken (support.google.com/a/answer/9981691).

Yahoo Sender Hub is Yahoo's equivalent, covering Yahoo Mail, AOL and Verizon addresses. It gives you Complaint Feedback Loop reports and sending insights rather than a single reputation score (senders.yahooinc.com). Yahoo's sender requirements set the same ceiling as Google for everyone: keep your spam-complaint rate below 0.3%, calculated from mail that actually reached the inbox (senders.yahooinc.com/best-practices).

Both require you to verify you own the sending domain before they'll show you anything: add the domain, add the DNS record each tool gives you, then wait for volume.

Why do emails go to spam in the first place?

Almost always it's one of five things: missing or misaligned SPF, DKIM or DMARC records; a spam-complaint rate that's crept above what Gmail or Yahoo tolerate; a sudden jump in sending volume from a domain with no history; a message that reads like a template blast; or a list with too many invalid or disengaged addresses. Google and Yahoo publish the exact authentication and unsubscribe requirements, and both expect bulk senders to support one-click unsubscribe with a working List-Unsubscribe header.

None of this is a mystery filter judging your intent. It's a small set of measurable rules, and every test on this page checks a different piece of them.

What should you do if a test shows spam?

1. Fix authentication first. Most placement problems trace back to SPF, DKIM or DMARC being missing or misconfigured, so check this before anything else.
2. Slow down. If you've just switched domains or tools, warm the domain up gradually rather than sending full volume on day one.
3. Clean your list. Remove addresses that bounced or never engaged; they drag your complaint rate up even when the message itself is fine.
4. Re-run the test. A spam score and a placement test both take minutes — confirm the fix before you send to anyone real.
5. Work through the full checklist if problems persist: Google and Yahoo's own deliverability rules, in order, usually finds the one setting that's wrong.

Spam complaints also have a legal side worth knowing: unsubscribe requests aren't optional under US, UK, EU or Canadian rules (see our plain-English summary — not legal advice), and ignoring them is one of the fastest ways to see your complaint rate climb.

Frequently asked questions

Does a perfect Mail-Tester score mean your email won't go to spam?

No. A 10/10 means your message and server passed the checks Mail-Tester runs, but the tool itself says a perfect score doesn't guarantee inbox placement, since individual mailbox filters and the recipient's own settings still apply.

How often should you run a placement test?

Before any campaign on a new or recently changed domain, and again after you fix anything a test flags. Once you're sending steady volume, Google Postmaster Tools and Yahoo Sender Hub are built to watch continuously, so you don't need to re-run a manual test every day.

Can you check if a specific email you already sent went to spam?

Not directly, unless you own the inbox it was sent to. For your own test inboxes, just open the spam folder. For a real recipient's inbox, there's no tool that can look inside it for you, which is exactly why seed-list tests exist: you send to inboxes you control before you send to anyone else.

Is Google Postmaster Tools free?

Yes. You verify a domain you own with a DNS record, and Google shows you spam rate, authentication and delivery data for mail you send to Gmail addresses from it, once your volume is high enough to register.

What's the fastest free way to check right now?

Send your actual email to the address Mail-Tester generates and check the score within a couple of minutes. It won't tell you where the message lands, but it will catch the authentication and content problems that cause most spam-folder landings in the first place.