Beginner's guide: fix your first subtitle file
This guide takes about five minutes. By the end, you'll have fixed your first subtitle file — and you'll understand what each button does.
What Subtitle Toolkit does
Subtitle Toolkit is a small program that cleans up subtitle files (the timed text you see at the bottom of a video). If your subtitles appear too early, too late, contain mistakes, or won't play on a device, this tool fixes them. Everything happens in your browser or in the installed app — your files are never uploaded anywhere.
What you need
- A subtitle file (usually ends in
.srt). - A web browser, or the downloaded app.
Step 1 — Open a subtitle file
Go to the Subtitle Toolkit app (or open the
installed version) and drop your .srt file onto the page,
or click to choose it from your computer. The file loads instantly —
it never leaves your device.
Step 2 — Fix the timing (the most common job)
If the subtitles appear a few seconds too early or too late, use the
Shift tab: enter how many seconds to move them (for
example 2.5 to delay them by 2.5 seconds) and apply it.
If they drift out of sync gradually, the Drift Correction
tab fixes that with two reference points — the app explains each field.
Step 3 — Check the wording
Use the Censor tab to replace a word everywhere at once, and the Validator tab to check the file against professional style guides (Netflix, BBC, WAI) — useful if you're preparing subtitles for a course, a channel, or an accessibility review. One click wraps any line that is too long.
Step 4 — Download the result
Press Download. Your corrected file saves to your computer, ready to use with the video. That's it.
Common questions
Is my file safe?
Yes. Nothing is uploaded. Processing happens entirely on your device.
Can I do several files at once?
The free tier handles one file at a time. Pro ($9, one-time, yours forever) processes whole folders at once and saves your settings.
What about subtitles inside a video file?
The Extract from video tab pulls embedded subtitle tracks
out of .mkv and .webm files.
Do I need an account?
No account is needed for the free tools. Pro uses a simple account so your purchase follows you between devices.
Where to get help
Write to rhls.softdev@gmail.com — real people answer, usually within a day.