Email subject line tester

Check a subject line for visible length, word count, line breaks and repeated punctuation. Preview it beside your sender name and preheader.

On your device · No account

Privacy details

Email subject line tester processes your input in this browser. Inputs and results are excluded from analytics. Recent tools save tool names, visit counts and last-visit times. Saved tools store only their names. Draft saving is optional and stays on this device; delete saved text with the draft controls. Loading text from a URL is optional and contacts that server; its URL and your IP address are visible to the server. An optional “Use in” action keeps a handoff in this tab. The next tool removes it on arrival and ignores it if more than a minute has passed.

Copy link includes the inputs you choose to share in the address. Anyone with that link can reopen them. Files and generated results are excluded. Password and key tools share settings only.

Your text

Options

Sender name

Preheader

Your result

Reset reloads the tool with its starting values and releases open files and device controls. Saved drafts stay on this device until you delete them.

Links include your inputs and settings. Anyone with the link can see them, so leave out private text. Files and generated results are left out; random draws run again.

Keyboard shortcuts

Updated 2026-09-19

Using Email subject line tester

Check a subject line for visible length, word count, line breaks and repeated punctuation. Preview it beside your sender name and preheader.

Next: Headline analyzer

A worked example

The email subject line tester changes "Hi" becomes "Visible characters: 2\nWords: 1\nLine breaks: 0\nRepeated ! or ?: 0\n\nSender\nHi\n".

Next: Hashtag generator

Before you use the result

No score predicts opens or delivery. Inbox truncation varies with device, font and app. Counts describe your text; this tool does not send an email.

Cite this page

Citation style

ToolOctopus. “Email subject line tester.” Updated 2026-09-19. https://tooloctopus.com/email-subject-line-tester.

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