Convert MP4 to WebM
Free, no sign-up, and your files never leave your device.
Drop your files here
Choose filesNothing is uploaded: everything happens in your browser
The video is processed by your device: allow a few seconds for a format change, longer for compression.
WebM is the web's open video format, light and played natively by Chrome, Firefox and Edge. Converting an MP4 to WebM is useful for a background video on a website or to meet a platform's requirements. The video is re-encoded to VP9 and the audio to Opus.
How to convert MP4 to WebM
- 1Drop your MP4 files in the box, or click to pick them. You can add several at once.
- 2WebM is already selected. Open the settings if you want to change the quality, the size or the background.
- 3Download each file, or everything at once as a .zip. Nothing was uploaded: the conversion happened on your device.
The formats
MP4
The universal video format. In H.264 with AAC audio, it plays on every phone, computer, TV and social network. It is the format to aim for when you do not know where the video will be watched.
WebM
The web's open video format, in VP9 or AV1 with Opus audio. It is light and plays in Chrome, Firefox and Edge, but less well on iPhones, in editing software and on some social networks.
Your files stay with you
The conversion runs in your browser, with your device's decoders. No file is uploaded, no copy is kept, and nobody but you sees your photos or videos. You can check it in the Network tab of your browser's developer tools: none of your files goes out.
Frequently asked questions
Is WebM lighter than MP4?
At equal quality, WebM's VP9 often weighs a little less than an MP4's H.264. The gain depends on the video.
Do iPhones play WebM?
Recent Safari plays WebM, but less reliably than MP4. For a website, offer both formats in the video tag.
Is the converter really free?
Yes, with no sign-up, no watermark and no limit on the number of files. The conversion runs on your device and costs us nothing, so there is nothing to charge you for.
Are my files sent anywhere?
No. They are read and converted in your browser, then saved straight to your device. No server receives them.
Is there a maximum size?
The limit is your device's memory. Photos and audio files go through without trouble; for a video of several gigabytes, a computer does better than a phone.
Does it work on a phone?
Yes, on iPhone and Android, in Safari, Chrome or Firefox. For video, an up-to-date browser is needed: it provides the decoders being used.
What next, with AI
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A camcorder shot 480 pixels wide, enlarged to 1080p by both video upscalers side by side. The full workflow, no account needed.
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