Subtitle tools

Why these run in your browser

Subtitle files are often confidential. An unreleased product demo, a client interview, a medical lecture or a legal deposition can all arrive as a caption file. Uploading that to an unknown server to change a comma into a period is a bad trade, so none of these tools has an upload endpoint. You can load a page, disconnect from the internet, and the tool still works.

Which tool do I need?

Most subtitle problems fall into one of five buckets. Find yours first — it saves you from converting a file you did not need to convert.

The file will not open or will not upload

That is a format problem. Players, editors and upload forms accept different things, and the mismatch is usually invisible until something refuses the file. Convert to the format your destination wants: SRT → VTT for the web, VTT → SRT for desktop editors, ASS → SRT for styled anime releases, SBV → SRT for YouTube exports, or TTML → SRT for broadcast and streaming deliverables.

The timing is wrong

Timing faults come in two shapes and they need different tools. A constant offset — everything is late by the same amount — is fixed with Shift Subtitles. A growing offset, where the subtitles drift further out of sync as the video plays, means a frame-rate or speed mismatch and needs Resync Subtitles, which resamples the whole timeline rather than moving it. If you are not sure which one you have, this guide walks through the diagnosis.

The text itself is broken

Stray timestamps baked into the dialogue, doubled blank lines, HTML tags, speaker labels, or mojibake from a file that was decoded as the wrong encoding. Clean Up Subtitles handles the first group, Remove Timestamps strips embedded timecodes from transcripts, and Fix Encoding repairs ’-style corruption.

I need to check it before delivery

Subtitle Timing Check produces a quality-control report: characters per second, minimum and maximum cue duration, line width and overlaps. It tells you what a client or platform would reject, before they do. This guide explains the thresholds and where they come from.

I need to restructure the file

Merging two files, splitting one at a point, or exporting the text for a translator. Use Merge Subtitles, Split Subtitles and SRT → CSV. If you are sending files out for translation, read the translation workflow guide first — the order of operations matters more than the tool choice.

All tools

What these tools will not do

They do not transcribe audio, translate text, or “improve” your wording. Every operation here is a deterministic transformation of text and timestamps: given the same input you get the same output, and nothing is invented. Automated rewriting of captions risks changing meaning, which is a far worse failure than awkward phrasing.

Conversions that are inherently lossy are documented on the relevant page rather than silently applied — WebVTT cue settings are dropped when converting to SRT, and ASS positioning and effects do not survive either. If you need those preserved, keep the original file.

Questions

Send them to the contact page. Bug reports with the input that broke are the most useful thing you can send — a subtitle file that fails is worth more than a description of a failure.

Last updated 2026-09-21. All tools run locally in your browser.