Check subtitle readability
Subtitles that are too long or too fast get skipped, not read. Paste SRT or VTT subtitles and the tool lists every cue that breaks one of four common subtitling limits.
Runs entirely in your browser. Your subtitles are never uploaded.
What the checker looks at
- Line length: at most 42 characters per line.
- Reading speed: at most 17 characters per second while the cue is on screen.
- At most two lines per cue.
- No overlaps: each cue starts after the previous one ends.
These limits suit scripts written with letters, such as Latin, Cyrillic or Greek. Chinese, Japanese and Korean subtitles use much shorter lines, so treat the results there as a rough guide.
No subtitles yet?
SonaFact turns audio and video into SRT and VTT subtitles timed to the spoken words, and shows which ones are too fast to read before you download. Start free, without a card.
Make subtitles from a recordingQuestions
- Are my files uploaded anywhere?
- Runs entirely in your browser. Your subtitles are never uploaded.
- Do I need an account?
- Every tool here is free and needs no account. All of them except the subtitle translator and WhatsApp audio to text work in your browser: your files are not uploaded anywhere.
Related tools
- Subtitle line length fixerRewrap subtitle lines that are too long: set the characters per line (e.g. 42) and lines per subtitle (e.g. 2). Subtitles that don't fit are split with their timing. Free, in your browser.
- Remove subtitle tags and SDHClean SRT or VTT subtitles: remove HTML and ASS tags, descriptions for the hard of hearing such as [music] or (laughs), song lyrics and speaker names. Free, in your browser.
- Split and merge subtitlesSplit a subtitle file at a time you choose, or merge several files into one with the times shifted correctly. SRT and VTT, free, in your browser.
- Dual-language subtitlesMerge subtitles in two languages into one SRT or VTT file, one language above the other — handy for learning a language. Free, in your browser, nothing is uploaded.