Subtitle checker CPS, lines and timing against Netflix rules.
This subtitle checker tests every cue in your SRT or VTT against streaming rules: 20 characters per second for English, up to 42 characters per line, two lines, 0.833 to 7 seconds on screen and a two-frame minimum gap. We flag every problem, add up the totals and suggest a fix.
Free, no sign-up- Average CPS
- Highest CPS
| # | Time | Text | CPS | Longest line | Lines | Duration | Problems | Suggested fix |
|---|
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How to check your subtitles
- 01
Paste or drop your subtitles
SRT, VTT and ASS all work. Formatting like italics is ignored in the count.
- 02
Pick a preset
Netflix English, Portuguese or Spanish, adult or kids. Set the frame rate and change any limit if your client has its own spec.
- 03
Fix with the suggestions
Every problem comes with a suggested fix. Apply timing and line break fixes in one go or download the CSV report.
How many characters per second should subtitles have?
Characters per second (CPS) is the number of characters in a subtitle divided by how long it stays on screen. We count letters, numbers, punctuation and spaces, and a line break counts as one space. A 34-character subtitle on screen for two seconds runs at 17 CPS.
Netflix's guides set adult programs at 20 CPS for English and 17 CPS for Portuguese and Spanish. Kids' programs go lower: 17 CPS in English and 13 in most other languages. Past that, viewers spend the whole video reading and miss the picture.
The math also tells you how long each subtitle needs: at 20 CPS, a 70-character sentence needs at least 3.5 seconds. If that time isn't there, shorten the text or split it into two subtitles.
| Subtitle | Characters | Duration | CPS |
|---|---|---|---|
| Good morning, church! | 21 | 2.0 s | 10.5 |
| Open your Bibles to John 3:16. | 30 | 1.8 s | 16.7 |
| For God so loved the world that he gave his one and only Son. | 61 | 1.0 s | 61.0 |
Which Netflix rules does the checker test?
The numbers below are an approximate reference from Netflix's public Timed Text Style Guides, reviewed September 2026. Each language has its own details, like line break and punctuation rules, and the guides change from time to time. Always follow the version your client sends: every limit in the tool is editable.
With two lines, keep them close in length and break at natural points: before a conjunction, after a comma, never between an article and its noun. When the text doesn't fit in two 42-character lines, the subtitle needs to be split.
| Rule | Adult English | Adult Portuguese and Spanish | Kids |
|---|---|---|---|
| Characters per second | 20 | 17 | 17 (13 non-English) |
| Characters per line | 42 | 42 | 42 |
| Lines per subtitle | 2 | 2 | 2 |
| Minimum duration | 5/6 s (0.833 s) | 5/6 s | 5/6 s |
| Maximum duration | 7 s | 7 s | 7 s |
| Gap between subtitles | 2 frames | 2 frames | 2 frames |
What are the minimum duration and gap between subtitles?
A subtitle that's too short just flashes by. The reference minimum is 5/6 of a second, about 0.833 s or 20 frames at 24 fps. At the other end, subtitles longer than 7 seconds tend to get read twice by viewers who think they missed something.
Between one subtitle and the next, the spec asks for at least two free frames. Without that breath, the eye doesn't notice the text changed. The gap depends on frame rate: two frames are 83 ms at 23.976 fps and 67 ms at 29.97, which is why the tool asks for your frame rate.
- Too fast: above the max CPS.
- Line too long or too many lines: over the line limits.
- Too short or too long: outside the duration range.
- Overlaps next or gap too short: under two frames before the next one.
How does the checker suggest a fix?
Every problem gets a concrete way out. If a subtitle is too fast and there's free time after it, we suggest how far to extend the out time without eating into the next gap. If there's no room, we tell you how many characters fit. Long lines get a new break or a split, and overlaps or short gaps get a new out time.
The fix button applies only the safe changes, timing, line breaks and empty subtitles, and downloads a new SRT. Cutting or splitting a line is the subtitler's call, so those stay flagged in the report for you to handle in your editor.
12 00:00:12,000 --> 00:00:13,500
Text: 38 characters in 1.5 s = 25.3 CPS
Suggested fix: extend the out time to 00:00:13,931More than a subtitle checker. Captions that read well from the start.
See also
Frequently asked questions
What is a subtitle checker?
It reads a subtitle file and tests every cue against reading rules: characters per second, characters per line, number of lines, duration and the gap between subtitles. Here you see problems cue by cue, with totals per rule and a suggested fix for each one.
How many characters per second should subtitles have?
Netflix's guides use 20 characters per second for adult English programs and 17 for Portuguese and Spanish, counting spaces and punctuation. Kids' programs use 17 in English and 13 in most other languages. If your client has a spec, it wins: every limit here is editable.
How many characters per line in a subtitle?
The most common limit, Netflix's included, is 42 characters per line with two lines at most. Vertical video reads better with shorter lines. The tool shows the longest line of each subtitle and suggests a new line break when it's over the limit.
What are the Netflix subtitle guidelines?
For English, the public reference is 20 CPS for adults, 42 characters per line, two lines, 5/6 of a second to 7 seconds on screen and two frames between subtitles. Treat it as an approximate reference: check the current guide your client sends and adjust the limits here.
What are the minimum duration and gap between subtitles?
The reference minimum is 5/6 of a second, about 0.833 s, and the maximum is 7 seconds. Leave at least two frames between one subtitle and the next. Pick your video's frame rate so the tool can turn those frames into milliseconds.
How is CPS calculated?
We divide the number of characters by the subtitle's duration in seconds. Spaces and punctuation count, a line break counts as one space and tags like italics are ignored. If your spec counts differently, turn off space counting.
Does the automatic fix change my text?
It doesn't change your words. It adjusts in and out times, redoes line breaks when the text fits in two lines and removes empty subtitles. Cutting, splitting or merging lines stays flagged in the report, because that's an editorial call.
Generate captions for your video automatically. With line breaks built for reading.
Upload a video or paste a YouTube link. We transcribe it word by word and you download the SRT and clips with burned-in captions, in the style you pick.
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