Free tool
Free SRT/VTT subtitle checker and SRT validator
Check an SRT or VTT file online for timing, overlaps, line length, reading speed, and subtitle structure.
Use this browser-only subtitle checker and SRT validator online before upload, client delivery, or editor handoff. It validates subtitle structure, flags readability issues, and can safely repair long line breaks without changing timestamps.
What the checker catches
- Invalid SRT/VTT structure
- Overlapping or negative timing
- Long subtitle lines
- High reading speed
- Mid-phrase line breaks
Checker or Script + Audio?
Use the free checker when an existing subtitle file mostly works and needs delivery review. Use Script + Audio when subtitle timing is wrong and you still have the approved script plus matching voiceover.
Subtitle checker FAQ
What is an SRT validator?
An SRT validator checks that a subtitle file is well-formed: valid SRT or VTT structure, sequential non-overlapping timing, and readable line length and reading speed. This free checker runs every validation in your browser.
How do I check an SRT file online for free?
Drop the .srt or .vtt file into the checker above. It runs in your browser with no upload and no sign-in, then lists structure, timing, overlap, line-length, and reading-speed issues.
Can I validate VTT files too?
Yes. The checker validates SRT and VTT subtitle files the same way.
Does checking my subtitle file upload it anywhere?
No. The checker runs entirely in your browser. Your subtitle file never leaves your device.
What subtitle formats are supported?
SRT and VTT files up to 2 MB.
Does fixing line breaks change my timestamps?
No. The free repair only changes where line breaks appear within a subtitle line. Start times, end times, and display text are unchanged.
When do I need the paid Script + Audio workflow?
When the subtitle timing itself is wrong. If subtitle boundaries don't match the speaker's pauses, re-aligning from script and audio is the only reliable fix. The free checker repairs formatting only.
Related free subtitle tools
Script + voiceover in. Timed subtitle files out.
Create precisely timed subtitles from Script + AudioTry TimedSubs with 15 free minutes. No credit card.
made by @woshiliyana1030