YouTube Caption QC
Check uploaded YouTube captions for reading speed, line length and overlaps so they're readable and don't trip auto-rejection.
YouTube captions (readability) — max 21 CPS, 42 chars/line, 2 lines, 0.7s min, 8s max
YouTube accepts most caption files but readability still drives watch-time: keep reading speed around 21 CPS, lines under ~42 characters and two lines max. This flags the cues that flash too fast or overflow on mobile, the difference between captions that help and captions viewers turn off.
🔒 Subtitles are processed entirely in your browser — never uploaded.
Check uploaded YouTube captions for reading speed, line length and overlaps so they're readable and don't trip auto-rejection.
About YouTube Caption QC
Check uploaded YouTube captions for reading speed, line length and overlaps so they're readable and don't trip auto-rejection. YouTube accepts most caption files but readability still drives watch-time: keep reading speed around 21 CPS, lines under ~42 characters and two lines max. This flags the cues that flash too fast or overflow on mobile, the difference between captions that help and captions viewers turn off.
How to use YouTube Caption QC
- 1Paste your subtitle file (SRT or WebVTT) into YouTube Caption QC, or open it from disk.
- 2The tool parses every cue and processes it in your browser.
- 3Review the result — flagged issues, converted output or statistics.
- 4Copy or download the corrected/converted file.
Why use YouTube Caption QC?
- ✓Runs entirely in your browser with instant, private results — no data leaves your device.
- ✓Built on a published reference: YouTube Help: caption file requirements; readability best practice.
- ✓100% free with no sign-up, no watermark and no usage limits.
- ✓Works on any device — desktop, tablet or phone — and keeps working offline once loaded.
Frequently asked questions
What does YouTube Caption QC do?+
Check uploaded YouTube captions for reading speed, line length and overlaps so they're readable and don't trip auto-rejection. YouTube accepts most caption files but readability still drives watch-time: keep reading speed around 21 CPS, lines under ~42 characters and two lines max.
Is my data private?+
Yes. YouTube Caption QC runs entirely in your browser — your inputs are never uploaded, stored or logged.
What standard or source is YouTube Caption QC based on?+
It follows YouTube Help: caption file requirements; readability best practice. Always confirm against the current official document, as specifications and rates can change.
Is YouTube Caption QC free to use?+
Yes — it is completely free with no account, no sign-up and no usage limits. There is no watermark and no paywall.
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