SRT to WebVTT Converter
FileFlip converts SRT to WebVTT entirely inside your browser, using FFmpeg compiled to WebAssembly. The file is never uploaded to a server: it is read off your disk, converted on your own machine, and saved back by the browser. That means no file-size limit, no queue and no account.
How do I convert an SRT file to WebVTT?#
- Drop your SRT file onto the converter at the top of this page, or click it to pick one from your computer. You can add as many as you like.
- Leave the target set to WebVTT and the conversion starts on its own. FileFlip downloads 30.8 MB of WebAssembly the first time and nothing after that, then runs FFmpeg on your own machine.
- Save the WebVTT file. Your browser writes it straight to your downloads folder, because there was never a server holding it.
Does converting SRT to WebVTT lose quality?#
No. Subtitle cues are text, and converting SRT to WebVTT rewrites the same timings and the same lines in the target's syntax. Anything WebVTT has no syntax for, such as positioning or styling, is dropped rather than degraded.
Is it safe to convert SRT files online?#
Yes, because nothing is uploaded. FileFlip converts SRT files inside the browser tab you already have open, using WebAssembly builds of the same engines a desktop converter would install. Your file is read from your own disk into the page's memory, and no request carrying it is ever made.
You do not have to take that on trust. Open your browser's network panel, run a conversion, and you will see the engine come down and your file go nowhere. There is no upload, no server-side copy, no retention window, and no account tied to what you converted.
How FileFlip works lists every engine, its version and its download size, and shows how to check for yourself that nothing leaves your machine.
What SRT to WebVTT actually does to the file#
Converting SRT to WebVTT runs on FFmpeg, downloads 30.8 MB of WebAssembly the first time and nothing after that, rewrites the cues as text in the target's syntax, keeps cue durations.
| Engine | FFmpeg |
|---|---|
| Conversion path | One step: SRT → WebVTT |
| Downloaded to your browser | 30.8 MB, once, then cached by your browser |
| Quality | Text preserved, unsupported styling dropped |
| You get back | One file |
| Where it runs | In a background worker, so the page stays responsive |
What survives the conversion
| What is in the file | This conversion | Why |
|---|---|---|
| Cue durations | Kept | Carried through into the converted file. |
What is an SRT file?#
An SRT file numbers each caption in order and gives it a start and end timecode measured in hours, minutes, seconds and milliseconds, with the line or lines of dialogue printed underneath and a blank line separating one caption from the next.
Use SRT when the file needs to open in the widest possible range of players and sites and doesn't need positioning or styling.
Convert away from SRT when the destination needs something SRT cannot hold, such as WebVTT's on-screen cue positioning or ASS's karaoke timing and typesetting.
What is a WebVTT file?#
A VTT file is a WebVTT text track: a WEBVTT header followed by timed cues, each with a start and end timecode and one or more lines of text, optionally carrying position, size and CSS-style settings that place and format the text on screen.
Use WebVTT for subtitles served to an HTML5 <video> element, where the browser reads the track natively and honors its cue positioning and styling.
Convert WebVTT to SRT when the destination is a player or device outside the browser that only expects plain, unpositioned captions.
SRT to WebVTT questions people ask#
What's the difference between SRT and VTT?
SRT is plain numbered captions with no styling, while WebVTT is the W3C's version of the same idea built for HTML5 video, adding cue positioning and CSS-style formatting. The two are close enough that converting SRT to VTT is a near-lossless, mostly mechanical change.
What program opens an SRT file?
An SRT file opens in essentially any video player, including VLC, and in dedicated subtitle editors like Subtitle Edit and Aegisub. Because it's plain text, it also opens in Notepad or TextEdit, though it will display raw timecodes rather than a preview.
Why does SRT have no styling or colors?
SRT was designed as a byproduct of ripping DVD subtitles to text, not as a typesetting format, so it only ever recorded a timecode and the caption line. That simplicity is why every player reads it; formats like ASS exist specifically to add styling back in.
Does an SRT file break if the video's frame rate changes?
No. SRT times each caption by clock time, in hours:minutes:seconds,milliseconds, so it stays in sync no matter what frame rate the video plays at. That's different from a frame-based format like MicroDVD SUB, which times captions by frame number and drifts out of sync if the frame rate doesn't match.