About Burn Subtitles
Burn Subtitles is a small tool for one job: take a video and a subtitle file and give you back an MP4 with the subtitles drawn into the picture. It runs entirely in your browser, so your video never leaves your device.
It is built and maintained by raychen. The video work is done by ffmpeg, compiled to WebAssembly, with libass drawing the subtitles. Nothing here is a wrapper around a paid service, and there is no server that sees your files.
The numbers on this site come from running the tool, not from guessing. The limits table lists what was actually tested, the browser it was tested in, and how long it took. If something on a page does not match what you see, the page is wrong, and that is worth reporting.
- Runs in the browser: ffmpeg.wasm (WebAssembly) with libass for subtitle rendering.
- Free, no watermark, no account, no upload.
- Analytics: Google Analytics 4 records page views and anonymous usage steps (style preset, resolution range, success or failure). It never receives your video, subtitle text or file names. Analytics cookies are off for visitors in the EEA, the UK and Switzerland.
- Input: SRT and WebVTT subtitles, or lines typed on the page. Output: H.264 MP4.
- Languages: Latin, Greek, Cyrillic, Simplified and Traditional Chinese, Japanese.
- Not supported: automatic speech recognition, Korean, Arabic, Hebrew, Thai and Indic scripts, ASS/SSA input.
FAQ
Is my video uploaded anywhere?
No. The video is processed by ffmpeg compiled to WebAssembly, running inside your browser tab. The file is never sent to a server, so it stays private and there is no upload wait. The only downloads are the page itself and the video engine (about 9 MB compressed, from the jsDelivr CDN).
Does the site use analytics or cookies?
Yes, basic usage analytics through Google Analytics 4. It records page views and anonymous steps, such as which style preset was chosen, ranges like video resolution, and whether a burn succeeded. It never receives your video, your subtitle text or any file name. The site is set up so that analytics cookies are not set for visitors in the European Economic Area, the United Kingdom and Switzerland. Elsewhere, Google Analytics may set cookies.
Is there a watermark or a sign-up?
No watermark, no account, no email. The MP4 you download contains your video and your subtitles, nothing else.
Can I change how the subtitles look?
Yes. Pick one of nine presets (Classic, Boxed, Bold yellow, Social, Pop, Minimal, Cinema, News, Karaoke) and adjust size, text colour, outline or box, and top or bottom position. A live preview on top of your video shows the result before you burn anything.
Can the words highlight one by one, like TikTok captions?
Yes. Choose Word by word under Motion and each word (each character for Chinese and Japanese) lights up in turn while the whole line stays on screen. The timing splits the subtitle's duration evenly between words, so it is an approximation, not true voice alignment. Fade and Pop in are also available.
My subtitles are early or late. Can I fix the timing?
Yes. Enter a time offset in seconds under Subtitles: a positive number delays every line, a negative number shows them earlier. The page also warns you when the subtitle file and the video do not match, for example when the first line starts after the video ends.
How big can the video be?
Measured in desktop Chrome on a recent Mac: a 20-minute 1080p video (1.2 GB) worked and took about 10 minutes; 1080p runs at roughly 2× real time and 720p about 4×. 4K works but is slow (a 30-second 4K clip took under 3 minutes). Phones have much less memory than computers: short clips of a few minutes are fine, long or 4K videos may fail. Files above 2 GB are not accepted.
Which subtitle and video formats work?
Subtitles: SRT (.srt) and WebVTT (.vtt). You can also type subtitles directly on the page. Video: MP4 and MOV were tested, including H.264 and HEVC phone recordings; WebM and MKV are accepted too. The result is always an H.264 MP4 with AAC or the original audio, the format iPhone, Android, Instagram, TikTok and YouTube all accept.
Does it create subtitles automatically?
No. This tool burns subtitles you already have (an SRT or VTT file) or subtitles you type in. It does not listen to your audio. If you need a transcript first, export an SRT from your editor or captioning service and bring it here.
Which languages are supported?
Latin, Greek and Cyrillic scripts (English, Spanish, French, German, Portuguese, Italian, Polish, Turkish, Russian, Ukrainian, Greek and more) work out of the box. Simplified Chinese, Traditional Chinese and Japanese also work: the page downloads an extra 8 MB font the first time your subtitles contain those characters. Korean, Arabic, Hebrew, Thai and Indic scripts are not supported yet and would show as empty boxes.