Email Subject Line Length Checker

Check email subject and preview text length while drafting campaigns, newsletters, and outreach.

Mavis Tools is built for quick utility work: paste the input, get the result, and move on. The page is static-first for speed, and the interactive work happens in your browser. That makes it useful for drafts, calculations, debugging snippets, and repeat everyday tasks.

This tool is intentionally focused. It does one job clearly instead of asking for an account or hiding the result behind a long workflow. Bookmark it if you need a fast email subject line tester that works on desktop and mobile.