Convert WebM to MP4 Online — No Upload, No Watermark
WebM is the open royalty-free container used by YouTube and Chrome. Converting to MP4 gives you a file that plays on every phone, browser, and editor without re-encoding at playback time.
Arrastra y suelta tu video aquí, o haz clic para buscar
Tamaño máximo: ~2 GB (según memoria)
Why convert WebM to MP4 here?
- WebM files often fail to play on Android, on the web, or when uploaded to social platforms. MP4 fixes that in one step.
- MP4 (H.264 + AAC) is the universal format that plays on iOS, Android, Windows, macOS, YouTube, Instagram, X, and every modern browser.
- This tool uses FFmpeg's H.264 + AAC pipeline — the same as professional workflows — with a default CRF of 23 for visually-lossless quality.
- Your WebM file never uploads. Convert sensitive or unreleased footage without sending it to a third-party server.
FAQ
Is this WebM to MP4 converter really free and without upload?
Yes. The tool runs entirely in your browser using FFmpeg compiled to WebAssembly. Your WebM 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 WebM to MP4 reduce quality?
The converter re-encodes to MP4 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 WebM to MP4 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 WebM files?
Not yet — the current flow converts one file at a time. Queue multiple tabs if you need parallel conversion.