Free · No sign-up · Local browser processing
Validate SRT and WebVTT subtitle files
Inspect existing captions for invalid or reversed timestamps, missing text, overlapping cues and incorrect SRT sequence numbers. Your original file is never altered.
Ready. Nothing uploaded.
Keep your original file. Structural checks do not guarantee audio synchronization or speech accuracy.
Why validate?
An SRT file with readable words may still fail in a video player due to timestamp or cue-syntax errors.
Checks provided
The tool parses standard cue blocks, checks boundaries and numbering, and reports out-of-order or overlapping intervals.
A pass is not a quality guarantee
Passing structural checks cannot prove speech accuracy, perfect synchronization or accessibility compliance. Test in your final video player.
Frequently asked questions
Is file content uploaded?
No. Validation is local to the browser.
Does validation change subtitles?
No. It only reports structural issues.
Can it judge speech-to-caption timing?
No. That requires listening to the source media.
Need new captions from speech?
Generate SRT subtitles from video/audio with LongScribe, then choose a converter, validator or timing repair tool for the downloaded file.