Check your subtitle files.
Find timestamp errors and reading-speed warnings in SRT or VTT files, then save a report. Your files stay in your browser.
Subtitle files
Changing a threshold takes effect on the next check.
Example report
Choose a file or try the sample to begin.
Choose a file, paste text or use the example to see findings here.
The offline edition contains the same Caption Check 0.1 checks as this free browser version, packaged for local use. It is available for £5 on Payhip.
What the report tells you
Format errors flag problems such as broken timestamps, empty cues and invalid sequence numbers. Each finding points to the source line and cue.
Review warnings flag overlaps, reading speed, line length and duration. An overlap may be intentional. Use your language and delivery requirements to decide what to change.
The checker leaves your files unchanged. It does not check audio alignment, translation or acceptance by a particular platform.
Privacy and file handling
Subtitle text is processed in this browser. The checker does not upload your files, use analytics cookies or store them between visits. Clear the page or close the tab to remove the current results.
Downloaded reports contain excerpts from your subtitles. Keep them as private as the source files.
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If you email us for help, your email and anything you choose to send are handled in our support inbox. You can ask us to delete that correspondence at hssilmoon.00@gmail.com. This note was updated on 6 September 2026.