Email Subject Line Tester
Score a subject line on length, words and style.
Runs in your browser. Nothing is uploaded — your input is processed on this device and discarded when you close the tab.
Email Subject Line Tester
How to use this tool
- Type your subject line.
- Press Generate for a score out of 100 with the length and word count.
- Adjust the wording if the score notes a problem, such as all-caps words or spam-style wording.
Worked example
For "Your March invoice is ready" (27 characters, 5 words, no all-caps word, no spam-style word), the score is 20 for length + 25 for word count + 20 for capitalisation + 25 for wording = 90 out of 100.
What this tool does not do / Limits
This score is a simple checklist, not a prediction of open rates. It does not test deliverability, does not read your audience, and cannot judge whether the subject matches the email content.
Frequently asked questions
Why is length scored?
Very long subjects get cut off on phones, and very short ones may say too little. The 30 to 50 character band scores best here.
Does a high score mean more opens?
Not necessarily. A clear, honest subject that matches the email matters more than any checklist score.
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