Convert MP4 to WebM
WebM is the open video format browsers play natively, and its VP9 codec is markedly more efficient than the H.264 in a typical MP4 — so the same clip usually comes back smaller at the same visual quality. This re-encodes your MP4 to VP9 video and Opus audio in a WebM, ready to embed on a page or hand to a tool that wants open formats.
Also known as: MP4 to WebM converter · MP4 to VP9 · MP4 to web video
Encrypted upload · deleted right after conversion
Your files are deleted automatically
Uploads are removed as soon as processing finishes, and converted files are deleted after 1 hour. Read our privacy policy.
How to convert MP4 to WebM
Step 1
1. Add your MP4 file
Drag your MP4 file into the box, or choose it from your device. It can be up to 95 MB.
Step 2
2. Choose your settings
Adjust Video quality (Balanced), or keep the starting values in brackets, which suit most files. More are under Advanced options.
Step 3
3. Press Convert to WebM
The work happens on our servers, and you can follow its progress. Long recordings take longer.
Step 4
4. Download your WebM file
Your upload is already deleted, and the result is deleted after one hour.
Worth knowing
VP9 is slower to encode than H.264, so a long clip takes longer than the reverse conversion. The result plays natively in every current browser, but not in some older devices and editors that expect MP4 — keep the MP4 for those. A clip with no audio stays silent.
Why convert MP4 to WebM?
- Embedding a video on a web page with an open, royalty-free codec
- Shrinking a clip for the web, where VP9 beats H.264 at the same quality
- Serving a WebM alongside an MP4 so every browser has a native source
- Handing video to a tool or platform that prefers WebM
MP4 vs WebM
| Property | MP4 | WebM |
|---|---|---|
| Container | MP4 | WebM |
| Video codec | H.264 | VP9 (more efficient) |
| File size | Baseline | Often smaller at the same quality |
| Audio | Kept | Re-encoded as Opus, kept in sync |
Frequently asked questions
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