Convert WebM to MP4
Free WebM to MP4 converter that runs entirely in your browser. No uploads, no signup required.
Drop WebM files here
or browse your device. Free, no signup required, no watermarks.
Files are processed on your device, never uploaded
Media conversions run on a full FFmpeg engine compiled to WebAssembly. The engine (~31 MB) downloads once on your first conversion, then everything runs locally.
Three steps
How to convert WebM to MP4
Add your files
Drop WebM files into the box above, or click it to browse. Add several to batch convert.
Convert
MP4 is already selected as the output. Hit Convert. Your browser does the work locally.
Download
Save each converted MP4 file. Pro ZIPs whole batches in one click.
WebM video
WebM
WebM is the open web video format built for browsers, with strong compression and no licensing fees.
MPEG-4 video
MP4
MP4 is the standard video format that plays everywhere: phones, browsers, TVs, and editing software.
Why convert WebM to MP4?
WebM is the open web video format built for browsers, with strong compression and no licensing fees. MP4 is the standard video format that plays everywhere: phones, browsers, TVs, and editing software. Converting from WebM to MP4 gets you the best of the target format wherever WebM falls short, whether that's compatibility, file size, or what your apps and devices can open. With FormatFusion the switch takes seconds and your files stay on your device the whole time.
Questions
WebM to MP4: common questions
Is this WebM to MP4 converter free?
Yes. It is completely free with no watermarks and no account required, for files up to 1 GB each. Convert one file or a hundred.
Is it safe to convert WebM files here?
Safer than any upload-based converter. The conversion runs locally in your browser, so your WebM files are never sent over the internet and never touch a server.
Will I lose quality converting WebM to MP4?
No. This conversion preserves your content, and MP4 output keeps everything the format supports.
Can I convert multiple WebM files at once?
Yes. Free converts up to three WebM files at a time. FormatFusion Pro batches without limits and downloads whole runs as a single ZIP.
Does it work on iPhone and Android?
Yes. FormatFusion runs in any modern mobile or desktop browser. No app install needed.