How to convert MP4 to WebM
- Drop your MP4 file on the box above or click the box to choose it.
- WebM is already selected. Pick a quality, and trim the start or end if you need to.
- Click Convert and watch the progress bar. Files that can be copied without re-encoding are ready in seconds.
- Click Download to save the WebM file.
Why convert MP4 to WebM?
MP4 is the most widely supported video format. With H.264 video and AAC sound it plays on every phone, computer, smart TV and website, and every social network accepts it.
WebM is an open video format made for the web, usually with VP9 or VP8 video and Opus sound. Browsers play it, but many phones, TVs and editing programs don't.
Choose WebM when the video is going on a website and you want an open, royalty-free format.
MP4 and WebM at a glance
| Format | MP4 | WebM |
|---|---|---|
| Type | Video | Video |
| Compression | Lossy | Lossy |
| Typical codecs | H.264 / H.265 + AAC | VP9 / VP8 / AV1 + Opus |
| Best for | video that plays on every device | an open format for web video |
| Opens in | Every device and app | All current browsers |
Good to know
- The video is re-encoded to VP9 or VP8 with Opus sound. Choose a lower resolution or quality for a smaller file for the web.
Questions about converting MP4 to WebM
Is the MP4 to WebM converter free?
Yes. It is free, with no sign-up, no watermark and no limit on how many files you convert.
Is my file uploaded?
No. Your browser reads and converts the file on your own device; nothing is sent to 4Dev or anyone else.
Is there a size limit?
Files can be up to 500 MB. The result is built in your device's memory, so very large files are better converted on a computer than on a phone.
Will converting to WebM reduce quality?
WebM is lossy, so it drops detail that is mostly inaudible or invisible. The default settings are a good balance; choose a higher quality or bitrate for archiving.
Which browsers can do this?
Current Chrome, Edge, Safari and Firefox on a computer, and Chrome or Safari on a phone. The format list only offers what your browser can actually create.
Is this tool free?
Yes, it's free to use. No signup, no email required. Get results on this page.
How do I get my result?
Use the tool on this page. Your result appears here; no email delivery is required.