Convert WebM to MP4
Turn WebM videos into widely compatible MP4, in your browser. No upload.
We're not interested in your data. A platform built free from surveillance.
Drop your files here
Choose filesConvert many at once · files never leave this browser
WEBM
Video and audio are converted entirely in your browser — longer or larger files take more time.
Quality
Why convert WebM to MP4?
WebM is common on the web but not supported by every editor or device. MP4 plays almost everywhere, making it the safe choice for sharing.
WebM vs MP4 at a glance
| WebM | MP4 | |
|---|---|---|
| Type | Video container | Video container |
| Compression | Lossy | Lossy |
| Introduced | 2010 | 2001 |
| Created by | MPEG / ISO | |
| Best for | Video on web pages and in browsers | Sharing video anywhere — phones, web, TVs |
Why WebM files cause trouble
WebM is Google's open video format, used by browsers, screen recorders and many download tools. Chrome, Firefox and Android play it fine, but iPhones, older Windows apps, PowerPoint, video editors and many upload forms expect MP4.
Converting re-encodes the VP8/VP9 video into H.264 and the Opus/Vorbis audio into AAC — the combination virtually every device can play.
Quality and speed
Video encoding is heavy work, and here it runs on your own device. A short clip converts quickly; a long, high-resolution recording can take several minutes on an older laptop or phone. Keeping the tab open and the device plugged in helps.
The High preset keeps the picture visually the same; lower presets make a smaller file, useful for messaging apps with size limits.
Is it safe?
Yes. This conversion runs entirely inside your browser, and your WebM file is never sent to a server. Metadata such as location is also removed automatically.
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How to convert WebM to MP4
- 1Drop your WebM files onto the box above, click it to choose files, or paste an image with Ctrl+V.
- 2Optionally pick a quality preset, or open fine-tune to set an exact quality or a maximum width and height.
- 3Conversion starts immediately and runs on your own device. Nothing is uploaded, so even large batches start without waiting for a transfer.
- 4Download each MP4 file individually, or grab everything at once as a single ZIP.
Frequently asked questions
Why is the MP4 bigger than the WebM?
VP9 in WebM is a very efficient codec, and the browser-based H.264 encoder favors speed. Use a lower preset if you need a smaller file.
Can I convert screen recordings from OBS or Chrome extensions?
Yes. Those are usually WebM files, and they convert like any other. If a recording has no sound, the MP4 will be silent too.
Is my video uploaded?
No. FFmpeg runs inside your browser as WebAssembly, so the video stays on your device.
Is it really free?
Yes. Converting WebM to MP4 is free with no sign-up and no watermark. The free plan handles several files per batch; an optional premium licence removes ads and raises the limits.
Are my files uploaded anywhere?
No. Your WebM files are read and converted by your browser on your own device. You can confirm it by opening your browser's developer tools and watching the Network tab while you convert: no file upload ever appears.
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