Free tool
Dubbing pacing checker for translated subtitles
Upload a translated SRT or VTT file and see which lines will sound rushed when dubbed, right in your browser.
This checks speech pacing only. It does not generate audio, translate text, or edit your subtitle file.
No upload. No login. Your subtitle text stays in this browser tab.
Checker boundary
This tool analyzes an existing translated subtitle file locally in your browser. It does not upload your file, call a translation or voice provider, or produce an audio track.
How pacing is estimated
Each cue's required speaking rate (characters per second) is compared against a per-language comfortable-speech band: 22 CPS for English/Spanish/other Latin-script languages, 18 CPS for Chinese, and 16 CPS for Japanese. Lines under 85% of the band are comfortable; up to 110% are tight; above that, rushed.
These bands are a speech-rate heuristic for planning, not a measurement of any specific voice or TTS engine.
Dubbing pacing checker FAQ
Why does dubbing sometimes sound rushed?
Translated lines are often longer or shorter than the original. When a line has too many characters for its time window, a dubbed voice has to speak faster than natural, which is why AI dubbing sometimes sounds rushed or robotic.
Does this tool generate the dubbed audio?
No. This free tool only checks pacing on an existing translated subtitle file. It does not call a TTS provider or produce audio.
What should I do with a rushed line?
Shorten the translated text for that line, or extend the cue timing if your workflow allows it, then recheck.