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Caption reading speed checker: CPS and WPM
Reading speed is visible characters or words divided by cue duration. This checker flags cues against the limits you choose, with presets from Netflix, BBC and TED guidelines. It does not certify compliance with any delivery specification.
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Published reading speed limits
Each value below was read on the guideline's own page on 2026-10-14. If a guideline does not state a number, the cell says so rather than converting one unit into another. Guidelines change, so confirm the current version with whoever you deliver to.
| Guideline | Audience | Max CPS | Max WPM | Characters per line | Lines | Notes |
|---|---|---|---|---|---|---|
| Netflix English (USA) Timed Text Style Guide | Adult programs | 20 | Not stated | 42 | 2 | Sections I.14 and II.17 for reading speed, plus the line length and maximum two lines rules. The guide no longer gives a words per minute limit. |
| Netflix English (USA) Timed Text Style Guide | Children's programs | 17 | Not stated | 42 | 2 | Same sections as adult programs. |
| Netflix Subtitle Templates guide (English templates) | Adult programs | 17 | Not stated | 42 | 2 | Section 23. Templates are the source for other languages, so the limit is lower. Line length is stated as 42 characters for most Latin alphabet languages. |
| Netflix Subtitle Templates guide (English templates) | Children's programs | 15 | Not stated | 42 | 2 | Section 23. |
| BBC Subtitle Guidelines, version 1.2.5 (March 2026) | General programmes | Not stated | 180 | 37 | 2 | Recommended speed is 160 to 180 words per minute, so the preset flags above 180. The 37 character line applies to broadcast (Teletext); two lines is recommended for landscape video and three for vertical. |
| TED Subtitling Tips | TED Translators | 21 | Not stated | 42 | 2 | Maximum 21 characters per second, break a subtitle longer than 42 characters into two lines, never more than two lines. |
Netflix general requirements also set a minimum duration of five-sixths of a second per subtitle event, a maximum of 7 seconds, and 2 lines maximum. The page leaves reading speed and character limits to the language guides.
Sources and date checked
- Netflix Partner Help Center: English (USA) Timed Text Style Guide (checked 2026-10-14)
- Netflix Partner Help Center: Timed Text Style Guide, Subtitle Templates (checked 2026-10-14)
- Netflix Partner Help Center: Timed Text Style Guide, General Requirements (checked 2026-10-14)
- BBC: Subtitle Guidelines (version 1.2.5, March 2026) (checked 2026-10-14)
- TED: Subtitling Tips (checked 2026-10-14)
How to use it
- 01
Load your captions
Paste or select an SRT/VTT file. The checker uses visible text rather than counting markup as words.
- 02
Set review limits
Pick a published guideline preset or enter your own characters/second, words/minute, line length and line count. Blank speed fields skip that check.
- 03
Review flagged cues
Read the caption in context. Shorten text or retime it without moving speech out of sync. Download the CSV for a review record.
A worked example
A 48-character caption shown for 2 seconds has a reading speed of 24 CPS. Extending it to 3 seconds gives 16 CPS, but the words must still match the action and speech.
What to check
- Character counts use Unicode code points, including spaces and punctuation; line breaks count as spaces for cue speed. Combined emoji can use more than one code point.
- Word counts use whitespace, so WPM is most useful for languages that separate words that way.
- Overlapping cues may be intentional. A flag means review, not automatic failure.
- Presets use values read from each guideline's own page (listed below the tool with the date checked). A guideline that gives only words per minute, like the BBC's, leaves the CPS field blank.
Questions
Is 20 CPS a universal caption limit?
No. Netflix's English (USA) guide sets 20 for adult programs and 17 for children's, its English template guide sets 17 and 15, and TED sets 21. The BBC recommends 160 to 180 words per minute instead. Verify the specification you deliver to.
Does the checker change my captions?
No. It reports issues so you can choose the edit. It does not rewrite words or move cue times.
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