Convert MP4 to WebM Online — No Upload, No Watermark
WebM (VP9 + Opus) is the open royalty-free format that Chrome, Firefox, and Edge prefer for web video. Converting MP4 to WebM is useful when you want a smaller file for a website or want to avoid H.264 licensing.
Drag & drop your video here, or click to browse
Max file size: ~2 GB (memory permitting)
Why convert MP4 to WebM here?
- WebM is typically 20–40 percent smaller than MP4 at the same visual quality.
- Every modern desktop browser plays WebM natively without plugins.
- No server-side re-encoding, no upload, no watermark.
FAQ
Is this MP4 to WebM converter really free and without upload?
Yes. The tool runs entirely in your browser using FFmpeg compiled to WebAssembly. Your MP4 file never leaves your device — open the DevTools Network tab to verify zero uploads. No signup, no watermark, no size cap beyond browser memory (~2 GB).
Will converting MP4 to WebM reduce quality?
The converter re-encodes to WebM with CRF 23 (visually lossless for most footage). If you need stream-copy instead (no re-encoding), use the Converter tool directly and toggle the codec-copy option.
How long does MP4 to WebM conversion take?
On an M2 MacBook, a 1-minute 1080p clip converts in about 8 seconds. 4K clips scale roughly linearly. Old machines are slower — processing uses your CPU and GPU, not our servers.
Can I batch-convert multiple MP4 files?
Not yet — the current flow converts one file at a time. Queue multiple tabs if you need parallel conversion.