About SyncMySubs

What this is

SyncMySubs is a set of free tools for subtitle files: converting between formats (SRT, VTT, ASS, TTML, SCC, EBU STL and a dozen more), shifting and rescaling timing, repairing garbled character encoding, extracting subtitle tracks from video, stripping SDH markup, checking reading speed, and a handful of related jobs. Every tool runs entirely in your browser.

Who makes it

SyncMySubs is designed, coded, and maintained by one independent developer — there is no company or team behind it. It launched in the summer of 2026, so it is a young site; what it lacks in history it tries to make up for in care. Every parser and converter here is written by hand for this site, down to the byte-level readers for broadcast formats like Scenarist SCC and EBU STL. When something is wrong, email me and it gets fixed.

Why it exists

Because the other options were frustrating. Most subtitle tools online make you upload your file to a server you know nothing about, wrap the whole thing in ads and pop-ups, or lock the useful part behind a sign-up. That always felt backwards for something as simple as nudging a timestamp.

How it works — and how to check

The site is plain HTML, CSS, and JavaScript with no backend at all. When you drop a file in, it is read and processed by JavaScript on your own device; there is no server that could receive it, so nothing is uploaded, nothing is stored, and no account exists to tie anything to. You don't have to take that on trust: open your browser's developer tools, watch the Network tab while you convert a file, or simply switch your connection off — the tools keep working. The details are written up in how we handle your files.

What it won't do

Honesty about limits is part of the design, so: the tools don't OCR subtitles that are burned into the video image or stored as bitmap tracks (PGS/VobSub), they don't auto-sync subtitles by listening to the audio — timing fixes here are precise but manual — and a conversion to a simpler format drops what that format can't hold, and says so before you download. If a job needs a heavier tool, the guides say which one rather than pretending.

How it stays free

A single unobtrusive ad below each tool, plus the occasional tip, covers the hosting. There is nothing to upsell: no premium tier, no locked features, no "free trial". If a tool here saved you some time, that's the whole point.