Reading Speed Checker

The Reading Speed Checker measures characters per second for every cue in the SRT you paste into the SRT Content box and reports the ones outside a comfortable band. Cues above Max cps are listed as too fast, cues below Min cps as slow, and a clean file returns a single all-clear naming the limits used. The output is a plain text report you can save as .txt.

Characters per second is the standard readability metric in professional subtitling because it captures what actually matters: how much text a viewer must absorb per unit of time. Broadcast style guides commonly target around 17 cps for adult programming and lower for children's content, with anything past 21 cps treated as uncomfortable. Translators working into verbose languages, e-learning teams captioning fast presenters and accessibility reviewers all need this number rather than a subjective impression.

For each cue the tool divides the subtitle text's character count by the cue duration in seconds and reports the rate to one decimal. Cues above your maximum are flagged as too fast; a cue below your minimum is only flagged when it actually contains text, so blank or whitespace-only blocks do not generate noise. Thresholds default to 21 and 8 cps when the fields are left empty, and every finding names the cue number and its measured rate. The check is diagnostic only, so no timings or text are rewritten.

Everything runs locally in your browser with no upload, and even a long file returns its report instantly.

• Characters-per-second per cue: Each subtitle's text length is divided by its display time and reported to one decimal, giving the same objective figure professional subtitling houses work to.
• Adjustable upper limit: The Max cps field sets what counts as too fast and defaults to 21, so you can tighten it to 15 for children's programming or relax it for a client with a looser spec.
• Adjustable lower limit: The Min cps field, defaulting to 8, catches cues that linger far longer than their text needs, which usually means an out point was never trimmed.
• Blank cues ignored for slowness: A cue with no real text is not reported as slow, so empty blocks do not clutter a report you are trying to act on.
• Named findings: Every issue is written as a sentence with the cue number, the measured rate and whether it is fast or slow, making the report usable as-is in QC feedback.
• Explicit pass message: A clean file returns a confirmation quoting the minimum and maximum used, which documents the standard the file was checked against.
• Read-only analysis: Nothing in your subtitles is modified, so the checker is safe to run against an approved master.
• Instant and private: The calculation happens in the browser with no server round trip and no file upload.

1. Paste the subtitles you want to assess into the SRT Content box, or press Load sample to see how the report reads on a file that contains a deliberately fast cue.
2. Set Max cps to your delivery specification, typically around 17 for a strict broadcast target or 21 for a general upper bound, and leave it empty to use the default of 21.
3. Set Min cps to the point below which a cue is suspiciously slow, with 8 being a sensible starting value.
4. Press Run and read the report, which either lists each problem cue with its measured rate or confirms that the whole file sits within your range.
5. Fix fast cues either by extending the cue's end time where the audio allows, or by condensing the wording, which is usually the better answer when the speech itself is quick.
6. Review any slow cues to see whether the out point should simply be pulled in so the caption does not hang after the line has finished.
7. Copy the report or download it as a .txt file for your QC record, then re-run after editing to confirm the file now passes.

Example 1 - a cue that is too dense to read. Forty-two characters in one and a half seconds is far past any broadcast limit, and the checker names it with the exact rate.

Cue text: "The committee reconvened the following morning."
Timing:   00:00:09,000 --> 00:00:10,500  (1.50s)

Report: Cue 4: 31.3 cps (too fast).

Example 2 - checking against a stricter house style. Setting Max cps to 15 and Min cps to 6 for a children's series surfaces cues an adult spec would have let through.

Cue 11: 18.4 cps (too fast).
Cue 26: 4.9 cps (slow).

The fix for cue 4 is either an extra second of display time or a shorter line such as "The committee met again next morning", which brings it under 21 cps without losing meaning.

• Captions people can actually finish: Keeping cues inside a sensible cps band is the single biggest factor in whether viewers read every line or give up halfway.
• Meets written delivery specs: Most broadcasters and streaming platforms state a maximum reading speed, and checking it yourself avoids a rejection you would otherwise discover after delivery.
• Objective feedback for translators: A cue number with a measured rate is far more actionable than telling someone a line felt rushed.
• Adapts to the audience: Because both limits are yours to set, the same tool serves children's programming, adult drama and technical training with different standards.
• Strengthens accessibility: Reading speed is central to whether deaf and hard-of-hearing viewers get equal access to the content rather than a technically present but unusable caption track.
• Keeps scripts confidential: The whole measurement runs in your browser, so nothing is uploaded to any service.