Will this subject line actually get opened?
Open rate starts with inbox placement. Forward your draft — we'll predict where Gmail puts it before your list sees it.
Free Email Open Rate Predictor
- Can you really predict my open rate?
- We predict the inbox placement that drives opens — where your email lands and how your subject line reads to filters and humans. Placement is the lever most open-rate problems actually come from.
- Why did my open rate drop?
- Often it's placement, not the subject: if more of your list lands in Promotions or Spam, fewer people ever see the email. We show the split so you know whether to fix the subject or the deliverability.
- How do I check a subject line before sending?
- Forward the email to your Mailtester address. We analyze the subject line and predicted placement, and offer an AI rewrite when the wording is hurting you.
€9.99 for AI deep-dives.
You forward it.
Paste the mailbox above into the test-send field in Beehiiv, Kit, Substack, Mailchimp — or your own inbox. Hit go. We never see your subscriber list.
We actually open it.
In real Gmail, real Outlook, real Yahoo. We watch where your email lands — Primary, Promotions, or Spam — using the same filters that decide whether your campaign worked.
You get a report.
Plain English. Three things to change, in priority order. Unlock the bundle and we generate a subject, body, and CTA rewrite in your voice — paste them back into your campaign before lunch.
Two different tests.
Most people mix them up.
If you've ever searched "email tester," half the results check whether the address is valid. We do the other thing — whether the email itself will reach the inbox once you press send.
You upload a CSV of subscribers. The tool tells you which addresses bounce. Great for cleaning a stale list before a re-engagement send.
You forward one email — newsletter, launch, client note — to a one-time mailbox. We open it in real Gmail, Outlook, and Yahoo and tell you which tab it landed in, plus what to rewrite before you send it to your list.
We check whether your sends will land. That's the whole product.
Free to score. Pay only for the AI deep-dive.
Forward any email and get the score — free and unlimited. Buy credits when you want the occasional AI deep-dive, or go €9.99/mo if you send regularly. Cancel from the same screen you upgrade on.
Send your next one to the inbox.
Takes less time than picking a hero photo. No card, no signup, no anything.