Convert MP4 to WEBM
WEBM is an open video format made for the web. Convert an MP4 to WEBM on your own computer, without uploading it.
- Never uploaded
- No size limit
- No watermark
- Free
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Quick answer: To convert MP4 to WEBM, drop the MP4 into the tool at the top of this page and press "Convert to WEBM". The picture and sound are converted for the web, which takes longer than other conversions. It happens in your browser, so the video is never uploaded. It is free, with no sign-up and no watermark.
Updated
How it works
- Drop your videoThe file is read on your computer, never uploaded.
- ConvertThe picture and sound are converted for the web. This takes a little longer than a plain repackaging.
- Download the WEBMPlays in Chrome, Edge, Firefox and Safari, and on most websites.
When WEBM is the right choice
Some web projects, website builders and tools ask for WEBM. Chrome, Edge and Firefox play it, and Safari on a Mac does from macOS 11.3 (2021). For iPhones and Apple apps, MP4 is the safer choice.
It takes longer, and the file is not smaller
An MP4 is usually just repackaged; WEBM needs the picture to be rebuilt, so it takes real time. Our one-minute 720p MP4 took 14 seconds, against 2 seconds for MOV. The WEBM was 30.8 MB, compared with 32.2 MB for the MP4: do not expect a big saving. To shrink a video, use the video compressor.
Need MP4 again?
WEBM to MP4 goes back. For a comparison of the two formats, see MP4 vs WEBM.
Measured, not promised
Measured on 21 Oct 2026 in Chrome on a 2019 Intel MacBook (an older laptop) with a one-minute 720p clip with spoken sound. Newer computers are faster; real footage varies. More results.
Why your video never leaves your computer
Your video is processed by your own computer, inside this tab, and never uploaded. That is why there is no size limit and no watermark. How it works.
Questions
Does WEBM look worse than MP4?
Not noticeably at the quality this tool uses.
Can I convert many files?
Yes, drop several and download a ZIP.
Can I convert several files at once?
Yes. Choose or drop several files together. They are converted one after another with the same settings, and you can download each one or all of them in one ZIP.
Is my video uploaded?
No. It is processed inside this browser tab and saved straight back to your computer.