# Convert MP4 to WebM

> Turn MP4 videos into open-format WebM files for lightweight web embedding.

Convert videos between MP4, MOV, MKV, and WebM in the browser. When the source and target share codecs, the streams are repackaged in seconds with zero quality loss (no re-encode); otherwise the video is re-encoded locally via WebAssembly — and the tool tells you which will happen before you start. No upload, no signup, no watermark. Handles files up to 700 MB.

## Frequently asked questions

### How long does MP4 to WEBM take?

It depends on the codecs inside your file. When they're compatible with WEBM, the conversion is a near-instant repackage with no quality loss. When they're not, the video is re-encoded in your browser, which takes roughly the video's length. The tool shows you which case applies before you start.

### Will the quality change?

If the video needs re-encoding, a small quality loss is unavoidable, but the converter uses a high-quality setting that is visually indistinguishable for most footage. Compatible streams are copied without any loss.

### Why is MP4 to WebM slow?

WebM only accepts VP8/VP9/AV1 video, and MP4 files almost always contain H.264 or HEVC — so the video must be re-encoded, which runs in your browser at roughly the video's length. For long videos, consider trimming first.

### Is it really free?

Yes. The converter is completely free, with no signup, watermarks, or limits. We make money from our video translation service, not from this tool.

### Do you upload my files?

No. The conversion happens locally in your browser using WebAssembly. Your file never leaves your device — you can even disconnect from the internet once the page has loaded.

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_Free · No sign-up · No watermark · Runs entirely in your browser — your file never leaves your device._

- Open this tool: https://easydub.video/tools/convert/mp4-to-webm
- All free EasyDub tools: https://easydub.video/tools