About SubAlign

Why we built it

Fixing a subtitle file is usually a small job: shift the timing a few seconds, convert SRT to VTT, repair some garbled accents. Yet the typical options are clunky desktop apps or sketchy "upload your file" websites that send your data to a server you know nothing about. We thought a faster, more private approach was possible, so we built one.

Modern browsers are powerful enough to do all of this work locally. SubAlign takes advantage of that: the processing happens on your own device, instantly, and your files never touch a server.

Privacy by design

This is the core principle behind everything here: your files never leave your device. There is no backend, no database and no file upload. When you use a tool, the entire operation runs in JavaScript inside your browser tab. Close the tab and the data is gone. It is private because it is technically incapable of being anything else.

What you can do here

• Format Converter — Convert between SRT, VTT and ASS/SSA in one click.
• Offset Shifter — Move every subtitle earlier or later by a set number of seconds.
• Framerate Converter — Fix PAL/NTSC speed drift by rescaling timings between frame rates.
• Encoding Repair — Repair garbled accents and mojibake by re-decoding to UTF-8.
• Merge & Split — Join multi-part subtitles or split one file in two.
• Cleanup Tools — Strip SDH tags, remove formatting, and check reading speed (CPS).

Free, and built to stay that way

SubAlign is free to use. Because everything runs in your browser, there are no server costs to pass on, which keeps the tools fast and the model simple. The site is supported by unobtrusive advertising so it can stay free for everyone.

Have feedback?

We are always improving the toolkit and adding new features. If you have run into a bug, have a subtitle format that does not convert cleanly, or want a tool that does not exist yet, we would genuinely like to hear it. Head to the contact page to get in touch.