Free subtitle tools that run in your browser
Subtitle tools that never upload your files
Convert between SRT, WebVTT and SBV, shift timing, fix framerate drift, merge split files and repair broken cues. Everything runs locally in your browser — free, instant, private.
Flagship: edit subtitles in your browser
Subtitle editorEdit text and timing cue by cue, with live reading-speed and overlap checks, find & replace, unlimited undo and autosave. Handles files with thousands of cues.Open the editorFormat converters
Timing & repair
- Shift timingMove every cue earlier or later by a fixed amount to fix a constant delay.
- Sync / fix driftRepair subtitles that drift further out of sync as the video plays.
- Merge filesJoin part 1 and part 2, or combine two tracks that share a timeline.
- Fix & validateFind overlaps, bad durations, empty cues and fast lines — then repair them.
Why these tools are different
Nothing is uploaded
Your subtitle files are parsed and rewritten by JavaScript running on your own machine. There is no server to send them to.
Tolerant parsers
Broken numbering, mixed line endings, dots instead of commas, missing WEBVTT headers, Windows-1252 encodings — the parsers accept what other tools reject and tell you what they fixed.
Batch friendly
Drop a whole season of files on a converter and download them one by one or all at once.
Which tool do I need?
Wrong format? A player or platform refuses your file: use a converter. Browsers and web players want WebVTT; desktop players, TVs and editors want SRT; YouTube exports SBV that nothing else reads; and a plain-text transcript is handy for notes and translation.
Subtitles too early or late by a constant amount? Shift them by a few seconds.
In sync at the start but drifting by the end? That is a framerate mismatch — sync with two reference points.
Two files for one video? Merge part one and part two, or combine two tracks.
Player shows garbage or skips lines? Fix overlaps, bad durations, empty cues and numbering.
Formats supported
All tools read SRT (SubRip), WebVTT and SBV (YouTube) and detect the format from the content, not the extension. Encodings are detected too: UTF-8 with or without BOM, UTF-16, and legacy Windows-1252 files fall back gracefully instead of turning accents into question marks. Output is always UTF-8 with consistent line endings.
Frequently asked questions
- Are these subtitle tools really free?
- Yes. There is no account, no file limit beyond a generous 20 MB per file, and no watermark. The site may show advertisements to cover hosting.
- How can the tools work without uploading my file?
- The parsers and converters are written in TypeScript and run inside your browser tab. The page is a static site; it has no server-side processing. You can verify this in your browser’s network inspector — no requests are made when you process a file.
- Which subtitle formats are supported?
- SRT, WebVTT and SBV as input, plus plain-text export. Formats like ASS/SSA, TTML and DFXP are not supported yet.
- Do the tools work offline?
- Once a tool page has loaded, you can disconnect from the internet and keep using it. Everything needed is already in your browser.