accessibility · free Companion App · local in this browser
Caption Line Checker
Check caption line length and reading speed against standard guidelines.
Privacy: This App does not send or save your entries. Do not enter passwords, codes, full account numbers, or private identifiers.
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Enter only the details needed for this task. Check them against the original source.
Your result
Your result will appear here.
Engine self-test
Running golden cases…
Source notes
- Described and Captioned Media Program / W3C WAI — Captioning Key
Caption quality guidelines recommend keeping line length around 32 characters per line and reading speed below 180 words per minute for general content.
Reviewed 2026-10-10. Different content types (education vs children) use different timing targets.
What this App does not do
This counts characters and estimates WPM. It does not edit captions.
This free App has no paid features. It does not contact an agency, employer, bank, seller, provider, or other person.