MP4
MP4 video
MP4 is the video container everything plays. It normally holds H.264 video and AAC audio, a pairing that phones, browsers, TVs and social networks all accept.
Opens in Every phone, browser, TV, console and editor
MP4 converterMP4 to WebM converter, without the upload.
Turn MP4 videos into WebM. It is converted in your browser, so the file never leaves your device.
Drop MP4 files here
or choose from your computer paste with Ctrl V
from Photos or Files
Ready · other file types work too0 bytes uploaded, ever
Convert to
- On your device · nothing is uploaded
- No account, no email
- Batch and ZIP download
- Free
How to convert MP4 to WebM
Add your MP4 videos
Drop MP4 files onto the box above, or click it to choose them. ToAny reads the file's contents to detect the type, so a wrong extension does not matter.
WebM is already chosen
Press Convert. Open Options first if you want to change the defaults. The work happens in this tab and can take a while for large files.
Download
Save the WebM, or download everything as one ZIP if you converted several files.
Why ToAny
Private by construction
The MP4 to WebM converter is part of this page and runs inside your browser. Your videos are never sent to ToAny or to anyone else.
No upload, no queue
Nothing has to travel to a server and back, so work starts the moment you press Convert. How long it takes depends on your device and the size of the file.
Free, without an account
No sign-up, no email address and no watermark. Add several files and download them together as a ZIP.
MP4 to WebM: what to expect
WebM is an open, royalty-free format that web developers use for background videos and that some wikis and open-source projects require. It plays in Chrome, Firefox, Edge and recent Safari. The video has to be re-encoded, because MP4's usual H.264 stream is not allowed in a WebM file.
The defaults suit most files. Under Options you can lower the resolution, trade quality against file size, remove the sound and trim the start and end. This is demanding work for a browser: a long or high-resolution file can take several minutes, and your device does all of it, so keep the tab open.
The conversion uses your browser's own video and audio codecs (WebCodecs), with hardware acceleration where the device has it; the file is read from disk as it goes and can be up to 2 GB. Where the browser lacks a codec, the page falls back to the compatibility engine. A video over 500 MB cannot be kept at full quality in browser memory; choosing a lower resolution or quality under Options lets it fit.
MP4 vs WebM
WEBM
WebM video
WebM is an open, royalty-free video format built for the web. It is a restricted form of Matroska holding VP8, VP9 or AV1 video. Browsers play it; iPhones, TVs and video editors often do not.
Opens in Chrome, Firefox, Edge and recent Safari; few TVs and editors
WebM converter| MP4MP4 video | WEBMWebM video | |
|---|---|---|
| Stands for | MPEG-4 Part 14 | WebM |
| Type | Video container | Video container |
| Compression | Lossy | Lossy |
| Usually contains | H.264 or H.265 video with AAC audio | VP8, VP9 or AV1 video with Vorbis or Opus audio |
| Introduced | 2001, by the Moving Picture Experts Group | 2010, by Google |
| Opens in | Every phone, browser, TV, console and editor | Chrome, Firefox, Edge and recent Safari; few TVs and editors |
| Best for | Sharing and uploading video anywhere | Royalty-free video on websites |
| File extension | .mp4 | .webm |
Questions
Are my videos uploaded anywhere?
No. The MP4 to WebM conversion runs inside your browser, on your own phone or computer. The file is not sent to ToAny or to anyone else.
Does converting MP4 to WebM reduce quality?
It depends on what is inside the MP4. When its video and audio are already in a form WebM can hold, they can be carried over without being compressed again. Otherwise they are re-encoded, which costs a little quality. Under Options you can favour quality or a smaller file.
Can I convert several MP4 files at once?
Yes. Add as many as you like, convert them together and download each result or all of them as one ZIP.
How do I convert MP4 to WebM on Windows, Mac, iPhone or Android?
The steps are the same everywhere because ToAny runs in the web browser: open this page in a current version of Chrome, Edge, Safari or Firefox, add the MP4 file, press Convert and save the WebM. There is nothing to install.
Is there a file size limit?
Yes. Files up to 2 GB are accepted, and a video over 500 MB needs a lower resolution or quality chosen under Options so the result fits in memory. Beyond that the limit is your device's memory, since nothing is uploaded; a computer copes with large files better than a phone.