Free MP4 to WEBM converter

Why convert MP4 to WEBM?

WebM is usually smaller at the same quality and is the right format for video you host on your own website.

How to convert MP4 to WEBM

1. Choose your MP4 file. Drop it on the box above, or tap to browse. You can pick several files at once.
2. Confirm the target is .webm. It is preselected when your browser can encode it; otherwise the closest available target is chosen. Adjust quality, size or the other options if you want to.
3. Convert and download. Press Convert, then Download. Your file stays on your device the whole time.

What is a .mp4 file?

MP4 carrying H.264 video and AAC audio is the one video format that plays essentially everywhere — phones, televisions, browsers, editing software and every messaging app. When something refuses to play a video, converting it to MP4 is almost always the fix.

What is a .webm file?

WebM is the open web video container, usually holding VP9 video and Opus audio. It is typically smaller than an equivalent MP4 and plays in every modern browser, which makes it ideal for video you host yourself and awkward for video you send to someone.

What to expect from this conversion

Every frame is decoded and re-encoded inside your browser, so a long clip takes a while and the tab must stay open. Setting a width of 1280 gives a much smaller file that still looks sharp on a phone.

Is it private?

Yes, by design. Every conversion happens inside your own browser using your device’s processor — there is no server that receives your MP4 file, so there is nothing for anyone to store, scan or leak. You can confirm it yourself: open your browser’s developer tools, watch the Network tab while you convert, and you will see no upload.

Questions about MP4 to WEBM

Is this MP4 to WEBM converter free?

Yes, completely. There is no account, no daily limit, no watermark and no premium tier.

Is my MP4 file uploaded to a server?

No. The conversion runs inside your own browser using your device's processor. The file is read from your disk, converted in memory and saved back to your disk — nothing is transmitted, so there is nothing for anyone to store.

Can I convert MP4 to WEBM online without downloading software?

Yes. This is an online MP4 to WEBM converter that runs in your browser, so there is nothing to install and no app to trust with your files. It works the same on a phone.

Does converting MP4 to WEBM lose quality?

Every frame is decoded and re-encoded inside your browser, so a long clip takes a while and the tab must stay open. Setting a width of 1280 gives a much smaller file that still looks sharp on a phone.

Can I convert several MP4 files at once?

Yes. Select as many files as you like and they are converted one after another in a single tap, with a download for each and a zip of all of them.

Can I convert MP4 to WEBM without FFmpeg or a script?

Yes — that is what this page is for. FFmpeg does the same job well if you already have it set up and thousands of files to process; for one file, or a handful, the browser is faster than installing anything.

Should I keep the original MP4 file?

Yes — keep it, converting never touches it. The reason to make a copy in another format is that MP4 plays nearly everywhere, but not inside every editor, browser or upload form.

How long does it take?

Roughly as long as the clip itself for high-definition video, because every frame is decoded and re-encoded on your own machine. Keep the tab in the foreground while it works.

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