WebM to MP4 Converter – Free & No Upload
Convert WebM screen recordings and downloads to MP4 locally in your browser — your video never leaves your device
WebM is common for browser screen recordings and web downloads, but video editors, iPhones and many apps don't accept it. This tool converts WebM (VP8/VP9) to a standard H.264 MP4 with AAC audio — entirely in your browser.
How to convert WebM to MP4
- Choose or drag in your WebM file — nothing is uploaded, it stays on your device.
- Click Start. H.264 sources are rewrapped losslessly in seconds; other codecs are re-encoded to H.264 in your browser.
- Download your MP4.
Frequently asked questions
Why won't my editor open WebM files?
WebM uses VP8/VP9 video and Opus/Vorbis audio, which many editors and Apple devices don't decode. Converting to H.264 MP4 with AAC audio makes the file universally editable and playable.
Is my video uploaded to a server?
No. The conversion runs entirely in your browser using WebAssembly (FFmpeg). Your file never leaves your device — that is also why there is no upload wait, no queue and no file-size pricing.
What is the maximum file size?
Up to 8GB on desktop browsers and 2GB on mobile. There is no limit on the number of files you convert, and no signup or watermark.