MP4 to WebM Converter
Convert MP4 to open-format WebM for HTML5 video and web apps.
Best for web developers embedding video that needs to avoid H.264 licensing.
Drop files here
or click to browse · paste from clipboard
Accepts .MP4 · Up to 1,000 files
How it works
Drop your files
Drag and drop, click to browse, or paste from clipboard. Up to 1,000 files at once.
Choose settings
Adjust quality, format, and other options to match your needs.
Click Convert
Everything runs in your browser via WebAssembly. MP4 to WebM Converter happens locally — no server involved.
Download
Download files individually or grab all at once as a ZIP.
Frequently asked questions
WebM is the preferred video format for web delivery — it uses VP9 video and Opus audio, both open and patent-free. Chrome, Firefox, and most Android devices play WebM natively. If you're preparing video assets for a web application or need an open-format alternative to MP4, WebM is the target.
VP9 encoding (the video codec inside WebM) is computationally intensive — significantly slower than H.264 at equivalent quality. A 5-minute 1080p file can take 2–5 minutes in the browser. This is a VP9 limitation, not a tool limitation.
No. Safari and iOS do not support WebM playback. If you need cross-device compatibility, stay with MP4. WebM is best for web applications where you control the browser environment or are targeting Chrome/Firefox users.
WebM wins when you need a patent-free format for an HTML5 `<video>` tag, when you're deploying to a Linux environment that avoids H.264 licensing, or when you want to pair VP9's compression efficiency with Opus audio for web streaming. If your audience includes iOS Safari users, serve MP4 as a fallback.
The conversion requires full VP9 re-encoding, so large or long files can take many minutes and are RAM-intensive in the browser. Converting very large batches simultaneously may cause the browser tab to crash. Process 3–5 large files at a time to stay within memory limits.
No. Conversion runs entirely in your browser using ffmpeg.wasm. Your video files never leave your device — the server only delivers the tool code.