The numbers in one table
Two published standards cover most of what independent creators need: Netflix's Timed Text Style Guides, written for professional subtitle delivery, and the Described and Captioned Media Program (DCMP) Captioning Key, written for accessible educational media. They agree on the broad shape (short lines, two lines at most, enough time to read) and differ on detail. Pick one and apply it consistently.
| Rule | Netflix (English USA and general) | DCMP Captioning Key | Sources |
|---|---|---|---|
| Characters per line | 42 | No character limit stated on the pages we read | [1][5] |
| Lines per subtitle | 2 maximum; keep to one line unless it exceeds the limit | No more than two preferred; three or four occasionally acceptable | [1][2][5] |
| Reading speed | Up to 20 characters per second (adult), 17 (children's) | Educational media: 130 wpm lower level, 140 middle, 160 upper | [1][4] |
| Minimum duration | 5/6 of a second (20 frames at 24 fps) | 40 frames (1 second and 10 frames) | [2][3][5] |
| Maximum duration | 7 seconds | 6 seconds (background music notation excepted) | [2][5] |
| Gap between subtitles | At least 2 frames; gaps should be 2 frames or half a second or more | Not stated on the pages we read | [3] |
Characters per second, explained
Characters per second (CPS) is the number of characters in a subtitle divided by how long it stays on screen. A full Netflix line of 42 characters at the adult limit of 20 CPS needs at least 2.1 seconds; two full lines (84 characters) need 4.2 seconds. At the children's limit of 17 CPS the same two lines need about 4.9 seconds. [1]
The pages we read do not say whether spaces and punctuation count toward CPS. Many subtitle tools count every character including spaces, which is the stricter reading, and that is how the examples in this guide are counted. If you deliver to a specific client, check their spec before relying on our counting.
DCMP measures speed in words per minute instead. Its presentation rate page says educational media should not exceed 130 wpm at lower levels, 140 at middle and 160 at upper levels, while keeping the original meaning, content and essential vocabulary. [4] 160 wpm is about 2.7 words per second.
Where to break a line
Netflix says to break lines after punctuation, before conjunctions and before prepositions. [1][2] It says not to separate a noun from its article or adjective, a first name from a last name, a verb from its subject pronoun, a prepositional verb from its preposition, or a verb from an auxiliary, reflexive pronoun or negation. [1] When several breaks are possible, it prefers a bottom-heavy pyramid, meaning the second line is the longer one. [1]
DCMP gives a similar list: break at a logical point where speech normally pauses, and keep a modifier with the word it modifies, a prepositional phrase together, a name with its title, and an auxiliary verb with its verb; do not end a line with a conjunction. [5] It also advises against ending one sentence and starting another on the same line unless both are very short. [5]
- Good break: after a comma, before 'and', 'but', 'because', or before 'in', 'on', 'with'.
- Bad break: 'the' at the end of line one and its noun on line two.
- Bad break: 'did' on line one and 'not' on line two.
- Bad break: 'Maria' on line one and 'Lopez' on line two.
Worked example: splitting one long sentence
Take this spoken sentence of 146 characters and 27 words, delivered in 7.5 seconds: 'If you export the subtitles before you fix the transcript, every typo ends up in the file your viewers read and in every translation made from it.' As one block it is about 19.5 CPS, but it is far too long for two 42-character lines and longer than both the 6-second and 7-second maximums.
A poor split puts 'If you export the subtitles before you fix' (42 characters) on line one and 'the transcript, every typo ends up in the file' (46 characters) on line two. Line two breaks the 42-character limit, and the break falls between a verb and its object instead of at the comma.
A better split uses three subtitles. Subtitle 1: 'If you export the subtitles' / 'before you fix the transcript,' (27 and 30 characters, breaking before the conjunction 'before'). Subtitle 2: 'every typo ends up' / 'in the file your viewers read' (18 and 29 characters, breaking before the preposition 'in', bottom-heavy). Subtitle 3: 'and in every translation made from it.' (38 characters, one line).
Timing at 20 CPS: subtitle 1 has 57 characters and needs at least 2.85 seconds, subtitle 2 has 47 and needs 2.35 seconds, subtitle 3 has 38 and needs 1.9 seconds. That totals 7.1 seconds of the 7.5 available, leaving room for two-frame gaps. At the 17 CPS children's limit the same text needs about 8.4 seconds, so for a younger audience you would condense the wording, for example cutting subtitle 3 to 'and into every translation.' if the meaning holds.
In words per minute the original sentence runs at 216 wpm, well above DCMP's 160 wpm upper level for educational media. [4] For an educational video following DCMP, editing for length is expected, provided meaning and essential vocabulary survive. [4]
| Subtitle | Line 1 | Line 2 | Characters | Minimum time at 20 CPS |
|---|---|---|---|---|
| 1 | If you export the subtitles | before you fix the transcript, | 57 | 2.85 s |
| 2 | every typo ends up | in the file your viewers read | 47 | 2.35 s |
| 3 | and in every translation made from it. | (none) | 38 | 1.90 s |
Timing details that trip people up
Netflix's timing guidelines require at least 2 frames between subtitles at any frame rate, and say gaps should be either 2 frames or half a second or more; at 24 fps, gaps of 3 to 11 frames must be closed to 2 frames by extending the earlier subtitle, a practice it calls chaining. [3]
In-times should land on the first frame of audio or within 1 to 2 frames of it, and when no subtitle follows, the out-time should ideally run at least half a second past the end of the audio. [3] Netflix also gives rules for shot changes, such as setting the in-time to the first frame of a cut when dialogue starts on or within half a second after it. [3]
Auto-caption tools usually produce good word timings but rarely apply these line-break and gap rules for you. Expect to review breaks by hand.
Applying the limits when you export from an editor
Descript's subtitle export dialog lets you choose SRT or VTT, show speakers, set the maximum characters per line and set the maximum lines per card. [6] Setting those to 42 and 2 gets you close to the Netflix shape, but the page does not mention controls for duration or break placement, so CPS and break quality still need a review pass. [6]
A practical review order: fix transcript errors first, then export with your line and character limits, then open the file in a subtitle editor that shows CPS per subtitle, and fix anything over your chosen limit by re-timing, splitting or condensing.
- Chosen standard written down (for example 42 characters, 2 lines, 20 CPS).
- No line over the character limit.
- No subtitle under the minimum duration or over the maximum.
- No subtitle over your CPS limit; condense or re-time where it is.
- Breaks checked against the keep-together rules.
- Gaps are 2 frames or at least half a second.
Questions before you decide
How many characters per line should subtitles have?
Netflix's English (USA) Timed Text Style Guide sets a limit of 42 characters per line with a maximum of two lines. DCMP's Captioning Key prefers no more than two lines but does not state a character limit on the page we read.
What is a good subtitle reading speed?
Netflix allows up to 20 characters per second for adult programs and 17 for children's programs. DCMP sets educational media at no more than 130, 140 or 160 words per minute for lower, middle and upper levels.
How long should a subtitle stay on screen?
Netflix sets a minimum of five-sixths of a second (20 frames at 24 fps) and a maximum of 7 seconds. DCMP sets a minimum of 40 frames and a maximum of 6 seconds.
Where should I break a two-line subtitle?
After punctuation, or before a conjunction or preposition. Do not split an article from its noun, a first name from a last name, or a verb from its auxiliary or negation, and prefer a longer bottom line.
Sources & verification
Product details and prices can change. Check the linked provider before buying.
- Netflix Partner Help: English (USA) Timed Text Style Guide Accessed 30 Oct 2026
- Netflix Partner Help: Timed Text Style Guide, General Requirements Accessed 30 Oct 2026
- Netflix Partner Help: Timed Text Style Guide, Subtitle Timing Guidelines Accessed 30 Oct 2026
- DCMP Captioning Key: Presentation Rate Accessed 30 Oct 2026
- DCMP Captioning Key: Captioning Text Accessed 30 Oct 2026
- Descript Help: Exporting subtitles Accessed 30 Oct 2026
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