Convert WebM to MP4
To convert a WebM to MP4, drop the .webm into the converter above and click Convert to MP4; the file downloads when it is ready. Video re-encoding is more than a browser can do for a large file, so it is sent to our server over an encrypted connection, converted, and then deleted. The output is a standard MP4 (H.264 video, AAC audio) that plays on the devices WebM does not.
Encrypted upload on an EU server, deleted within about an hour.
Drop your WebM hereChoose a WebM to convert
It becomes a MP4 right in your browser, up to 500 MB
Limits, published exactly
| Where it runs | On our server, over an encrypted connection; deleted within about an hour. |
|---|---|
| Free conversions | 2 per day without an account, 5 per day with a free account. |
| Max file size, free | 500 MB |
Why convert WebM to MP4?
WebM is the open, royalty-free video format built for the web, and it is what a lot of sites and tools hand you when you save or export a clip. The catch is reach beyond the browser: Apple never embraced it, so iPhones, iPads, Safari and many TVs and editors will not play a WebM. MP4 with H.264 is the format those devices all accept, so converting is the step that takes a web clip into the rest of your life.
What is WebM?
WebM is the web-native, royalty-free video format Google introduced in 2010, built on the VP8/VP9 video codecs and Vorbis or Opus audio. Every modern browser plays WebM directly, HTML5 video embraces it, and no patent licensing is attached to it anywhere in the chain. Outside browsers it is less at home: many desktop players, editing suites and devices still prefer MP4.
What is MP4?
MP4 is the default container of modern video: phones record into it, cameras export it, and every browser, TV and editing tool plays it, usually carrying H.264 video and AAC audio. Being a container, an MP4 is really a box around separate video and audio tracks, which is why useful conversions include not just other video formats but also pulling the audio track out on its own.
Quality and what to expect
The video is re-encoded to H.264 and the audio to AAC, the universally supported pair. This is a re-encode, not a lossless container swap, so there is a small generational quality step at the high-quality default, traded for playing everywhere. WebM commonly uses the VP8 or VP9 video codec, which is exactly what many devices cannot decode; the H.264 output removes that barrier. Dimensions are preserved (evened for H.264), with fast-start so it plays before fully downloading. On privacy, this is a server conversion: the upload is encrypted, the input is deleted immediately after conversion and the MP4 within about an hour, and the dropzone marks it a server conversion before you start.
WebM to MP4 FAQ
Why will not my WebM play on my iPhone?
Apple never added WebM support to iOS or Safari, so a WebM simply will not open there, even though the file is fine. Converting to MP4 (H.264) gives you a file those devices play natively.
Will the video lose quality?
A small, usually imperceptible amount: the video is re-encoded to H.264 at a high-quality setting rather than copied losslessly. The trade is a file that plays on the Apple and TV devices a WebM cannot reach.
Is my video uploaded to a server?
Yes. Re-encoding a large video cannot run in a browser, so the WebM uploads over an encrypted connection, converts, and is deleted: the input immediately after conversion, the MP4 within about an hour. The dropzone labels it a server conversion before you start.