Convert MP4 to WebM
Ethical Tube's free MP4 to WebM converter turns MP4 videos into WebM, an open video format made for the web. It runs entirely in your browser, so your videos are never uploaded, and it's free with no sign-up or watermark.
Files are converted on your device and never uploaded.
- Price
- Free
- Uploads
- None, it runs on your device
- Sign-up
- Not needed
- Batch
- Unlimited files
- Output
- WebM (VP9 + Opus)
- Install
- Nothing to install
How it works
How to convert MP4 to WebM
Add your MP4 files
Drop MP4 files onto the converter, click to choose them, or paste from the clipboard. Add as many as you like.
Check the settings
WebM is already selected. Keep the original resolution or pick a smaller one, and choose a quality.
Download your WebM videos
Each file gets its own download button as soon as it's ready. Download all saves everything in one ZIP file.
The formats
MP4 and WebM at a glance
What is an MP4 file?
MP4 is the most widely supported video format. It usually holds H.264 video with AAC audio, a combination that plays on practically every phone, computer, TV, and website. It balances quality and file size well, which is why most cameras, phones, and editors export to it. It opens in everything: Windows Media Player and Films & TV, QuickTime and Photos on Mac, iPhone, Android, smart TVs, VLC, and every major website and video editor.
What is a WebM file?
WebM is an open, royalty-free video format from Google, built for the web. It holds VP8, VP9, or AV1 video with Opus or Vorbis audio, and it's what Chrome and many screen recorders, including Ethical Tube, save by default. QuickTime, iMovie, and some editors can't open it. It opens in Chrome, Edge, Firefox, and Safari, VLC, YouTube, Google Drive, and editors like Shotcut and Kdenlive. QuickTime and iMovie can't open it.
Good to know
What changes when you convert MP4 to WebM
- If the video and audio already use codecs that WebM supports, they're copied without re-encoding, which is lossless and fast. Otherwise the video is converted to VP9 video with Opus audio.
- Only the main video and audio tracks are kept. Subtitles, chapters, and extra audio tracks aren't carried over.
- Re-encoding uses your device's hardware video encoder when it has one, which is often faster than real time.
- Copy-protected (DRM) files can't be converted.
- Very long videos can run out of memory, especially on phones.
FAQ
Questions, answered
Is this MP4 to WebM converter free?
Yes. It's completely free, with no sign-up, no watermark, and no limit on how many files you convert. It costs Ethical Tube nothing to run, because the conversion happens on your own device rather than on a server.
Are my files uploaded anywhere?
No. The conversion runs inside your browser with Mediabunny and your browser's WebCodecs video encoders, so your files never leave your device. Once the page has loaded, it even works offline.
Does converting MP4 to WebM lose quality?
Not if the codecs already fit: then the video and audio are copied as they are, with no loss. When they have to be re-encoded, the default quality keeps the result visually close to the original. Pick a higher quality for footage you plan to edit.
How long does it take?
When the video can be copied without re-encoding, a few seconds. Otherwise it depends on the video's length and resolution and on your device. With a hardware encoder, a 10-minute 1080p video usually takes a few minutes on a laptop.
Can I convert several MP4 files at once?
Yes. Add as many as you like. They're converted one after another, and you can download each WebM file as soon as it's ready or all of them in one ZIP file.
Does it work on iPhone, Android, Mac, and Windows?
Yes. It works in current versions of Chrome, Edge, Safari, and Firefox. Phones handle short clips well, and long or 4K videos convert best on a computer.
What can open a WebM file?
Chrome, Edge, Firefox, and Safari, VLC, YouTube, Google Drive, and editors like Shotcut and Kdenlive. QuickTime and iMovie can't open it.
Is there a file size limit?
There's no upload limit because nothing is uploaded. The practical limit is your device's memory: everyday files are fine, and a computer can usually handle videos up to about 2 GB.
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