Tools Guides Use Tools →
Subtitle utility

SRT Validator Online

Validate SRT subtitles online and check upload errors, timestamp format, cue order, and numbering.

Free No signup Browser-local

SRT input

No signup. No server upload. Browser-only processing.

Drop a subtitle file here or choose one manually

Supports SRT, VTT, and ASS where relevant to the tool.

Selected file: sample.srt

Validation report

Runs locally in your browser

Selected file: sample.srt

Workflow notes

How to use this SRT validator tool

Use this before upload when YouTube, an editor, or a video platform rejects an SRT file. The validator creates a local report for timestamp format, cue order, numbering, and parse errors, then points you toward cleanup or timestamp repair when the file needs changes.

  1. Add a supported subtitle file. Upload or paste a supported subtitle file (.srt, .txt), or load the sample input to see the expected structure.
  2. Run the SRT validator tool. Use the browser-based converter or repair action to process the subtitle file locally on your device.
  3. Review and download the output. Check the first few cues, the middle of the file, and the final cue before copying or downloading the result.

Input and output checklist

  • Use a complete subtitle file with valid cue timing when possible.
  • Keep a copy of the original file before replacing it in your workflow.
  • Review the first few cues, the middle of the file, and the final cue after export.
  • Test the downloaded output in the destination player, editor, or upload form.

Common mistakes to avoid

  • Expecting a validator report to modify the subtitle file.
  • Ignoring dot-based timestamps in an SRT upload workflow.
  • Skipping cleanup or timestamp repair when the report flags upload-blocking errors.

All processing runs in your browser, so the subtitle or video file does not need to be uploaded to a server. That is useful for client review files, unreleased videos, internal training material, and other caption workflows where the text should stay on your device.

When to use this tool

Use this free SRT validator before upload to find timestamp errors, out-of-order cues, numbering problems, and parse issues without sending the file to a server.

  • Check SRT files before YouTube or platform upload.
  • Find comma, arrow, and timestamp separator problems.
  • Confirm how many subtitle cues can be parsed.
  • Diagnose SRT files that an editor or upload form rejects.

FAQ

Is this SRT validator free? +

Yes. You can validate SRT subtitles for free in your browser without signup or upload.

Does the validator change my subtitle file? +

No. It outputs a text report. Use the SRT timestamp fixer or cleaner if you want a repaired file.

Can this help when an SRT file will not upload? +

Yes. The report checks common upload blockers such as malformed timestamps, cue order problems, and numbering issues so you know what to fix next.

Can it detect dot-based timestamps? +

Yes. It flags dot-based milliseconds because standard SRT uses commas.

Does it count parsed cues? +

Yes. The report includes how many subtitle cues were detected.

Are my SRT files uploaded to a server? +

No. Validation runs locally in your browser, so your subtitle file stays on your device.