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SRT / VTT Caption Reading Speed (WPM) Checker

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Parse an SRT or WebVTT file and report the words-per-minute reading speed of every cue, flagging ones that exceed common broadcast accessibility guidelines.

Paste or upload an SRT or WebVTT file and this parses every cue's timing and text to compute the words-per-minute and characters-per-second reading speed each cue actually demands. Cues faster than roughly 180 words per minute or 20 characters per second are flagged, common thresholds from broadcast accessibility guidance for how fast a viewer can comfortably read on-screen text before it disappears. Both thresholds are adjustable, since some house styles are stricter or looser than the defaults. This is distinct from the shipped SRT/WebVTT Subtitle Converter, which converts between formats and shifts timing but doesn't evaluate reading speed at all.

srtvttsubtitlescaptionsaccessibilitywpmvideo

How to use SRT / VTT Caption Reading Speed (WPM) Checker

  • 1.Paste your SRT or WebVTT file, or upload it directly.
  • 2.Optionally adjust the words-per-minute or characters-per-second thresholds to match your own style guide.
  • 3.Check the flagged cues in the table, each one highlighted where its reading speed exceeds a threshold, and either extend the cue's duration or shorten the text.

Frequently asked questions

Where do the default 180 WPM and 20 CPS thresholds come from?
They're common broadcast and streaming accessibility guidelines for how fast an average viewer can read on-screen captions. They're not a hard technical limit, so both thresholds are adjustable if your house style is different.
Does this fix the timing for me?
No, it only flags which cues are too fast to comfortably read. You'll need to either extend the cue's duration or shorten its text; the tool tells you which cues need attention, not how to rewrite them.
How are HTML-style tags like <i> handled?
They're stripped before counting words and characters, so italic or bold styling in a cue doesn't inflate its apparent length.
Does it work on both SRT and WebVTT?
Yes, the format is auto-detected from the WEBVTT header, and WebVTT-only blocks like NOTE, STYLE, and REGION are skipped since they carry no readable cue text.

Use via API, SDK, or MCP

cURL# Free: 1,000 req/day · Pro: 10,000 req/day
curl -X POST https://api.utilix.tech/v1/tools/caption-reading-speed-checker \
  -H "Authorization: Bearer utx_live_..." \
  -H "Content-Type: application/json" \
  -d '{"input":"1\n00:00:01,000 --> 00:00:04,000\nHello there.\n"}'

Get an API key from your dashboard · Full API docs →

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