Find subtitles that are too fast to read. This tool measures each cue's reading speed in characters per second (CPS) and flags any that exceed your threshold, so you know which lines to shorten or give more time. It also flags durations and overlaps. Runs entirely in your browser.
— or paste the subtitle text below —
Netflix's timed-text style guide caps adult content at 17 characters per second; many broadcasters aim for 15–17 CPS. Above that, viewers cannot finish reading before the subtitle disappears. The default here is 17; lower it for children's content or raise it for expert audiences.
CJK languages pack more meaning per character, so their reading-speed limits are lower — typically around 9 CPS rather than 17. If you are checking CJK subtitles, set the threshold lower. The tool counts characters excluding spaces, which is the standard basis for CPS.
17 characters per second is the common ceiling for adult Latin-script content (Netflix standard). Use around 9 for Chinese, Japanese, or Korean, and lower for children's content.
Characters in the cue (excluding spaces and formatting tags) divided by the cue's duration in seconds.
Yes. The same tool flags cues that are too short, too long, overlapping, or too close together. See also the Duration Checker.
Processing happens in your browser. Subtitle input/output samples are sent to GeekLink for troubleshooting.
These free tools handle files you already have. GeekLink extracts hardcoded subtitles via OCR, transcribes and translates with AI, and burns subtitles into video — batch-processing dozens of videos, all locally on your Mac or Windows PC.
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