What is WebM?
A plain-English definition, and the tools that work with it.
WebM is an open, royalty-free video format built for the web. It typically produces smaller files than MP4 at similar quality, which makes it great for fast-loading web video, though MP4 still has broader support across devices and editors.
- WebM is often smaller than MP4 at the same quality, ideal for websites and background video.
- Support is strong in modern browsers but weaker in some apps and older devices. MP4 is the safe universal choice.
- Converting between WebM and MP4 is common depending on where the video needs to play.
Tools for WebM
Free, private and in your browser. No sign-up.
WebM to MP4
Convert WebM to MP4 (H.264) in your browser, the universally compatible format that plays on iPhones, in editors and on social. Preview the result and download. Nothing is uploaded.
Video Converter
Convert video between MP4, WebM, MOV, AVI, MKV and GIF in your browser with FFmpeg. Pick a target format, tune MP4 quality, preview the result and download. Nothing is uploaded.
MP4 to WebM
Convert MP4 to WebM (VP9) in your browser: a leaner, royalty-free format that streams natively in modern browsers. Tune the quality, preview the result and download. Nothing is uploaded.
Video Compressor
Compress video in your browser with FFmpeg, shrink MP4, MOV, WebM and MKV files with a simple quality slider, see the exact bytes and percentage saved next to a live preview, then download. Nothing is uploaded.
WebM problems we solve
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Frequently asked questions
Related terms
- MP4MP4 is the most widely supported video format, a container that holds video and audio together. Because virtually every device, editor, browser and platform plays MP4, it's the safe default for sharing, uploading and playing video anywhere.
- GIFA GIF (Graphics Interchange Format) is an image format best known for short, silent, looping animations. It's limited to 256 colors, which keeps simple loops small but makes it a poor choice for detailed video or photographs.
- BitrateBitrate is how much data is used per second of audio or video, measured in kbps or Mbps. A higher bitrate means more detail and a larger file. A lower bitrate means a smaller file with more compression. It's the main dial for the quality-versus-size trade-off.
Keep exploring
Related tools
Problems we solve
Definitions
From the blog
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Common tasks
Try WebM to MP4
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