SRT subtitle editor and validator
Open or paste your subtitle file: you'll instantly see the errors that make YouTube or your editor reject it, plus readability warnings. Fix timings and text and download the result as SRT or VTT.
Your file never leaves your browser: nothing is uploaded to a server.
What the validator checks
- Errors: unreadable timestamps, subtitles that end before they start, overlaps with the next one and out-of-order cues. These are what usually make a platform reject the file.
- Readability warnings: more than 2 lines, lines over 42 characters, cues shorter than 1 second or longer than 7, and reading speeds above 21 characters per second.
- Non-sequential numbering in SRT (fixed automatically on download).
How to fix an SRT step by step
- 1Open the file with Open file, drag it in or paste its content.
- 2Press Fix automatically to sort, renumber, remove empty cues and trim overlaps.
- 3Review the remaining warnings and edit each cue's text or timings (format
00:00:01,500). - 4Download the result as SRT or VTT.
Don't have the file yet?
You can generate it automatically from the video with our subtitle tool: upload the video, review the text and download the SRT. Then run it through this validator if you're publishing on a demanding platform.
Don't have the subtitles yet?
Generate your video's SRT automatically with AI. 15 minutes free, no sign-up.
FAQ
Frequently asked questions
Is my file uploaded to a server?
No. The editor runs entirely in your browser: the file is read and processed on your device.
Why does YouTube reject my SRT?
The most common causes are badly written timestamps, cues that end before they start, or the wrong encoding. The validator catches the first two, and the downloaded file is always saved as UTF-8.
How many characters should each line have?
The most widespread guideline is a maximum of 2 lines and about 42 characters per line, with a reading speed of up to 17–21 characters per second.