Netflix CPS Reading-Speed Checker

What CPS is, and why it's the subtitle failure nobody notices until QA

Characters per second — CPS — is the single most common reason a technically perfect subtitle track still fails delivery QA. A caption can have correct spelling, clean timing and zero overlaps, and still be unwatchable if the text on screen changes faster than a viewer can read it. CPS measures exactly that: how many characters appear per second the cue is on screen, calculated as characters ÷ duration in seconds. It is invisible in a script review and invisible on a waveform — it only shows up when someone actually watches the cut with captions on, which is why it slips through so often and why streamers like Netflix enforce it as a hard delivery gate rather than a style suggestion.

How Netflix counts characters

Netflix's Timed Text Style Guides count every character in the displayed text toward CPS — letters, numbers, punctuation and spaces. A line like "Wait — did you hear that?" counts all 25 characters, spaces included, not just the letters. What does not count is a line break: a two-line cue's character total is the sum of both lines' visible characters, with the line-break itself contributing zero. For Korean, the count is by Hangul syllable block (each block is one reading unit, not one Latin-alphabet character), and for Japanese and Chinese the count is by full-width character, since CJK glyphs each carry far more visual information per character than a Latin letter — which is exactly why their ceilings are so much lower.

The pinned ceiling table

Netflix does not apply one CPS number worldwide. Each language gets its own ceiling, split further by adult and children's content:

Worked example: a 68-character English line held on screen for 3.400 seconds is 68 ÷ 3.400 = 20.0 CPS — sitting exactly on the English adult ceiling, so it passes, but barely. Translate that same line into Spanish, French, German, Italian or Portuguese without shortening it and it fails outright (17 ceiling), and it fails Korean, Japanese and Chinese by an even wider margin. This is the trap dubbing and localization teams hit constantly: a line timed to pass in English routinely blows the ceiling once translated, because most languages need more characters than English to say the same thing, while the ceiling itself only gets stricter.

Netflix revises these guides periodically per language, so treat this table as a working reference and confirm the current numbers on the official Netflix Timed Text Style Guide hub before final delivery — the values here are current and pinned deliberately narrow (no invented languages) so nothing here is a guess.

Why children's content is stricter

Every ceiling above drops for children's programming, because younger viewers read more slowly and are less practiced at parsing subtitle syntax (dashes for two speakers, ellipses for interruption, etc.). English drops from 20 to 17 CPS, Korean from 12 to 9 — roughly a 25–30% cut across the board. If a project is rated for a younger audience, always select the Children's ceiling; grading a kids' show against the adult number will pass lines a child audience genuinely cannot keep up with.

When a line fails: condense, split, or extend — and when each is right

A cue that exceeds its CPS ceiling has exactly three fixes, and picking the right one matters:

• Condense the text when the wording is longer than it needs to be — tighten phrasing, drop filler words, use contractions. This is almost always the first move and the one Netflix's own guidelines prefer, since it doesn't touch timing at all.
• Split the event into two cues when there's genuinely too much dialogue for one screen and condensing would lose meaning — each half then gets its own duration and its own CPS budget.
• Extend the timing only when there's actual video real estate to spare (no hard cut, no dialogue overlap) — pushing the out point later lowers CPS but can drift a cue into the next shot or line of dialogue, so it's the fix of last resort, not the first one reached for.

The duration rails

Independent of CPS, Netflix bounds how long any single event can sit on screen: a minimum of 5/6 of a second (≈833 ms) so a cue isn't gone before it's readable, and a maximum of 7 seconds so a static caption doesn't linger and read as a mistake. A line can pass CPS and still fail delivery on duration alone, which is why this checker flags both independently.

1. Paste the subtitle text exactly as it appears on screen, spaces and punctuation included.

2. Enter the in and out timing in SRT or SMPTE form, then pick the language and the audience.

3. Read the CPS figure against its ceiling, then check how the same cue sits for line length in the CPL Line-Length Checker.