Drop an SRT, VTT, ASS, or SSA file here, or click to select
Validate timing, empty captions, overlapping cues, and common format structure.
Check subtitle files before publishing or importing them into editing software. The fixer can normalize SRT numbering, sort cues, repair small overlaps, add a WebVTT header, and validate common ASS/SSA event structure.
Subtitle files often fail because of small formatting problems: missing sequence numbers, overlapping timestamps, blank captions, wrong timestamp separators, missing WebVTT headers, or malformed ASS Dialogue lines. These issues can make platforms reject the file or show captions out of order.
Validation is useful before uploading captions to video platforms, sending subtitles to a client, importing translations into an editor, or converting between SRT and VTT.
The fixer handles common structural cleanup, but it cannot judge translation quality or whether the text matches the audio. Always preview important subtitles with the final video.
It supports SRT, WebVTT, ASS, and SSA. Checks include invalid or reversed timestamps, overlapping cues, empty captions, SRT numbering, WebVTT headers, and required ASS event fields.
It can sort cues, renumber SRT entries, prevent overlaps, add a WebVTT header, and repair some invalid end times. It cannot judge language accuracy or automatically synchronize captions to audio.
No. Validation and cleanup run in the current browser tab. You can copy or download the fixed subtitle after reviewing the issue report.
Related tools: ASS to SRT · SRT Time Shifter
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