WebM to MP4 Converter – Free, Fast & Private
Convert WebM screen recordings and downloads to MP4 locally in your browser — your video never leaves your device
How to convert WebM to MP4
Choose or drag in your WebM file — nothing is uploaded, it stays on your device.
Click Start Converting — H.264 sources are rewrapped losslessly in seconds; other codecs are re-encoded to MP4 (H.264/AAC).
Download your standard MP4 file.
About WebM to MP4 conversion
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.
Frequently asked questions
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.
Yes — that's the most common use. Screen recordings from Chrome, Loom-style tools and browser APIs are usually WebM; converting to MP4 lets you edit them or share them anywhere.
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.
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.
Yes — completely free and unlimited, with no watermark, no signup and no daily quota. Because the conversion runs on your own device instead of our servers, there are no processing costs to charge for.
If the source already contains H.264 video, the file is rewrapped without re-encoding and finishes in seconds, even for gigabyte files. Other codecs are re-encoded in parallel WebAssembly workers, which runs at roughly real-time speed on a modern computer.
Yes. It runs in any modern browser — Chrome, Safari, Edge or Firefox — on Windows, macOS, ChromeOS, Linux, iOS and Android. There is nothing to install.
AAC and MP3 audio is copied over unchanged. Other audio codecs (PCM from cameras, Vorbis, Opus…) are converted to AAC so the resulting MP4 plays everywhere.