Email Subject Line Analyzer: Length, Spam, Preview

Free with no sign-up. Everything runs in your browser: nothing is uploaded or stored.

How it works

1. Paste a subject line. Everything is analyzed as you type.
2. The score weighs length, shouting caps, punctuation, emoji, and known spam phrases.
3. Preview rows show roughly how much of the line survives in phone and desktop inboxes.
4. Findings list each fix in plain language, worst first.

Exact truncation depends on the client, the font, and the reader’s settings, so the previews are typical widths rather than guarantees. The habit that always holds: put the point in the first few words.

Writing a subject line that survives the inbox

Name the specific thing, not the category: “a quote on the battery recall” beats “media opportunity”. Skip claims the email cannot support, and avoid stacking urgency words, because both make a personal message read like bulk mail.

If the subject leans on a personalization token, check the merged result before sending: an unmerged [first name] is worse than no token at all. The word counter helps keep the whole message short enough to read in one glance.

Related tools

Scan the full message with the spam word checker, or start from a proven message in the template library. All free tools live at /tools.

Frequently asked questions