Caption Check
Check an SRT or VTT caption file
Open a caption file, fix names and typos fast, catch lines that are too long, too quick or on top of each other, shift the timing and save it as SRT, VTT or text.
Free. Works in any browser, on a phone or a computer. What you put here stays on your device.
About Caption Check
The limits it applies
- At most 42 characters on a line, and 2 lines on screen.
- Each caption on screen for 1 to 7 seconds.
- Reading speed at most 20 characters a second.
- No caption overlapping the next one.
These are common subtitle guidelines, not YouTube rules; YouTube accepts longer lines, but viewers read them less well.
How to use it
- Open the SRT or VTT file you downloaded from YouTube Studio or your editor.
- Show only the lines with problems, and fix names and words the automatic captions got wrong right in the line.
- Captions early or late? Shift every time by the same number of seconds.
- Download the file as SRT or VTT and upload it to YouTube Studio, or as plain text for a transcript.
Questions
- Is my file uploaded?
- No. The file is read and saved in your browser.
- Do I need the video?
- No. The video is optional; open it beside the captions to check timing by eye.
- Can it convert SRT to VTT?
- Yes. Open either kind and download the other; the words and times stay as they are.
- My captions are out of sync. Can it fix that?
- When every line is early or late by the same amount, yes: shift every time by that many seconds and download the file again.