Paste a subject line and get an instant, itemized score plus a live preview across Gmail, Outlook, and Apple Mail. See exactly where it gets cut off and what to fix, before you hit send.
Type a subject line above to see your score and a live inbox preview.
Transparent scoring
Most subject line checkers hand you one black-box percentage. This one shows its work. Every subject line starts at 100 points, then gains or loses points for each thing filters and readers actually care about:
Character limits
No email client publishes an official character limit. These are typical cut-off points driven by pixel width. The takeaway: keep your subject under 50 characters and front-load the hook inside the first 33 so it survives even the tightest mobile apps.
| Email client | Surface | Subject cut-off |
|---|---|---|
| Gmail (desktop) | desktop | ~70 chars |
| Apple Mail (Mac) | desktop | ~65 chars |
| Outlook (desktop) | desktop | ~55 chars |
| Apple Mail (iPhone) | mobile | ~46 chars |
| Gmail (iPhone app) | mobile | ~37 chars |
| Gmail (Android app) | mobile | ~33 chars |
Best practices
Front-load the value. Put the most important word first. On a phone you may only get 33 characters, so "3 days left on your trial" beats "Just a quick note about your account and the trial that is ending".
Be specific, not clever. A concrete detail ("You used 47% of your credits") outperforms vague hype ("An amazing update inside") almost every time, and it dodges the spam-word problem entirely.
Write like a person. The subjects that win in a B2B inbox read like a note from a human, not a banner ad. Sentence case, no ALL CAPS, at most one emoji.
Match the preview text. Your subject and preview text are one unit. Use the preview to extend the subject, not repeat it. Test both together in the inbox preview above.
Steal these
The fastest way to learn what works is to see the same message written badly, then well. Each pair below takes a subject that trips filters or gets ignored and rewrites it to be specific, human, and short enough to survive on a phone. Paste any of the good ones into the tester above to see the score for yourself.
SaaS trial ending
The before stacks ALL CAPS, spam phrases (act now, free), and three exclamation marks. The after is specific, personalized, and lands inside the 33-character mobile cut-off.
Abandoned cart
Ellipsis and 'now' read as pressure. The rewrite uses a light question to spark curiosity and reassures instead of nagging.
Newsletter / content
Hype words (amazing, incredible) say nothing. The after promises a concrete, useful payoff, which is what earns the open.
Re-engagement
Shouting plus 'limited-time offer' pattern-matches to spam. A short, human question outperforms a promotional shout in a cold inbox.
Product announcement
'Revolutionary' and 'you won't believe' are empty and spammy. Naming the actual benefit is clearer and dodges the trigger words entirely.
Webinar invite
Free, ALL CAPS, and stacked exclamation marks are three separate red flags. The rewrite sets a clear time expectation and topic, no hype needed.
Meisa makes every send subtly unique so filters cannot flag it as a bulk blast, sends to your most engaged contacts first, and automatically resends to non-openers. These are the exact deliverability levers behind higher open rates, and they run on your own sending.
Own your sending. Land in the inbox. 14-day money-back guarantee.
FAQ