Free tool
Email Subject Line Tester
Paste a subject line and get an instant score out of 100 on length, spam-trigger words, capitals and clarity, with plain fixes for anything that drags it down.
Runs in your browser. Nothing you type is sent anywhere.Type above to see the score update live. Try one of your real subject lines.
A great subject line still needs a great email under it
The subject wins the open. The reply still has to be worth the time or the next one gets skipped. ReciteMail drafts the whole email in your own voice in seconds so the message lives up to the subject you just sharpened.
What makes a good subject line
A subject line has one job: earn the open without spending the reader's patience or tripping a spam filter. The lines that do it well share a handful of habits.
- Front-load the meaning. Phones show as few as 30 characters. Put the point in the first three or four words, before any cut-off.
- Keep it under about 40 characters. Short reads as a person. Long reads as a campaign and campaigns get ignored.
- Say one specific thing. "Invoice 2048, due Friday" beats "An important update regarding your account". Specific earns trust before the email is even open.
- Skip the sales-promotion words. Free, act now, limited time and their cousins are the words filters and people both distrust.
- Lose the shouting. ALL CAPS, triple exclamation marks and a row of emoji all read as noise, not urgency.
Words that trigger spam filters
No single word sends an email to spam on its own anymore. Filters score the whole message. A subject line stacked with sales-promotion language still pushes that score up so it is worth knowing the usual suspects. One is usually fine. A handful together is the problem.
Subject lines that work and why
- "Quick question about order 2048" is specific, short and sounds like a person. The reader knows exactly what it is.
- "Following up on Tuesday's quote" gives a clear reference and a reason, no fluff.
- "Your March invoice is ready" is plain, expected and easy to act on.
- "Two options for the kitchen deadline" hints at value inside without overselling.
Testing a cold or follow-up subject? The line is only half the job. The follow-up email guide and the reply templates cover the message that has to earn the reply once the subject earns the open. Or try the email signature generator next.
Common questions
How long should an email subject line be?
Aim for about 40 characters or fewer. Desktop inboxes show roughly 60 characters of a subject line and phones show as few as 30, so the front of the line has to carry the meaning. Anything past 60 characters gets cut off with an ellipsis and the reader never sees the end. Short and specific beats long and complete.
What words trigger spam filters in a subject line?
Modern filters weigh the whole message rather than a banned word list. Subject lines heavy on sales-promotion language still raise the score though. Common culprits are free, buy now, act now, limited time, guarantee, risk-free, cash, cheap, winner, congratulations and anything with multiple exclamation marks, ALL CAPS or a currency figure. One of these is usually fine. A stack of them in one line is what looks like spam.
Is this subject line tester really free and private?
Yes. The tool is free with no signup and it runs entirely in your browser. The subject line you type is never sent to a server, never stored and never seen by anyone. You can even disconnect from the internet and it still works.
Does a good subject line guarantee my email gets read?
No. The subject line only wins the open. The email underneath still has to be worth the time or the next one gets ignored. A strong subject on a weak email trains people to skip you. Get both right: a clear subject and a reply that sounds like a person wrote it.
Write the email, not just the subject
ReciteMail learns your voice from mail you have already sent, then drafts replies that sound like you in seconds. It runs on your own PC, never connects to your inbox and nothing sends without you. Free for 7 days, no card needed.
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