Subtitle Quality Checker
Open or paste an SRT or WebVTT subtitle file to check timing, overlaps, line length and reading speed. Set your preferred limits and optionally provide video duration, then download a detailed report. Your subtitle text stays in your browser.Read more ↓Show less ↑
Free to use · No account or login required · No ads
Your media stays private: processed in your browser, never uploaded to our servers.
Frequently asked questions
Which subtitle problems are checked?
The checker flags malformed or reversed timestamps, empty cues, chronological ordering, overlapping intervals, excessive reading speed, long lines and more than two lines per cue. Enter a video duration to also flag cues ending after the video.
Are 20 characters per second and 42 per line universal rules?
No. These defaults are editable readability guidelines. Platform, language, accessibility and broadcaster requirements vary. Character counts include spaces, exclude markup, and count Unicode code points; they are not a language-specific reading assessment.
Can I correct subtitles here?
Yes. Edit the SRT or VTT text and run the check again. This tool downloads a JSON review report; it does not automatically rewrite timing or burn captions into video. SRT/VTT files up to 5 MB are processed locally without signup.
