Writing & Content · Free tool
Email Subject Line Tester
Test subject lines for length, spam triggers, and emoji safety online. Preview Gmail and iPhone rendering instantly — free tool, no sign-up required.
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What it does
Test an email subject line for length, spam-trigger words, excessive punctuation, and emoji rendering. Previews how the line looks on iPhone Mail and Gmail's inbox, where most subject lines get truncated around 40–60 characters. Essential for newsletter campaigns and cold outreach.
For general headlines use headline analyzer. For ad character limits, ad copy length checker. Pair with character counter for a clean count.
Embed this tool on your siteShow snippetHide
Paste this snippet into any page. Loads on-demand (lazy), no tracking scripts, and sized to most dashboards. Replace the height to fit your layout.
<iframe src="https://freetoolarena.com/embed/email-subject-line-tester" width="100%" height="720" frameborder="0" loading="lazy" title="Email Subject Line Tester" style="border:1px solid #e2e8f0;border-radius:12px;max-width:720px;"></iframe>How to use it
- Type or paste a subject line.
- Read the score and the flagged issues (length, spam words, emoji risk).
- Compare the iPhone and Gmail previews.
- Iterate until the score and previews both look clean.
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Learn more
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