The name people see in their inbox. It is the same for every version.

Runs in your browser. Nothing you type is uploaded or sent.

Version A

Our measure: up to 60

Our measure: 35 to 110

Version B

Our measure: up to 60

Our measure: 35 to 110

Up to four versions, checked side by side. The tool does not write subject lines and cannot tell which one people will open.

Type a subject line to check it

A phone and desktop inbox sketch, the length, capitals, emoji, Re: and Fwd:, merge tags and claims that need proof appear here as you type. Or press Try an example.

Free Email Subject Line Checker. Runs in your browser, no sign-up. Open the full tool on DigitalSnot →