WebM to MP4 Converter
Convert WebM videos to MP4 format in your browser.
Drop your WebM file here
or click to browse · max 500 MB
Settings
Slower = better compression, longer conversion time
128k for speech · 192k for general use · 320k for music
FFmpeg WASM (~25MB) will be downloaded on first use and cached by your browser.
WebM to MP4 Converter
Converts WebM video files to MP4 format using H.264 codec. MP4 is the most widely supported video format, playable on virtually every device, browser, and media player. H.264 encoding ensures maximum compatibility with smart TVs, game consoles, and mobile devices.
What is it used for?
- Making videos playable on all devices including older smartphones and TVs
- Uploading to social media platforms (Instagram, Facebook, TikTok)
- Importing into video editing software like Premiere Pro, Final Cut, DaVinci Resolve
- Sharing videos via email or messaging apps
- Playing videos on devices that don't support WebM
Step-by-Step Guide
- Click the upload area or drag and drop your WebM file
- Adjust quality, encoding speed, and audio bitrate in the settings panel
- Click 'Convert to .MP4' to begin conversion
- Monitor progress with the conversion progress bar
- Preview and download your MP4 file
How it works
Upload a WebM file and click Convert. FFmpeg WASM encodes with H.264 video codec and AAC audio codec at CRF 23 for high quality. Preview the result and download the MP4 file. All processing happens in your browser.
WebM vs MP4 (H.264)
| Feature | WebM | MP4 (H.264) |
|---|---|---|
| Device Support | Limited (modern browsers) | Universal (all devices) |
| Social Media | Not accepted | Accepted everywhere |
| File Size | Smaller | Slightly larger |
| Video Editing | Limited support | Full support |
| Streaming | Web only | All platforms |
Tips & Best Practices
- CRF 23 is the default and provides visually lossless quality for most content
- Use 'fast' or 'faster' encoding preset for quicker conversion, 'slow' for better compression
- Audio bitrate of 128kbps is sufficient for speech, use 192-320kbps for music
Frequently Asked Questions
Why convert WebM to MP4?
While WebM is great for web playback, MP4 (H.264) is universally supported across all devices, TVs, game consoles, and social media platforms. If your video needs to play everywhere, MP4 is the safest choice.
What quality settings should I use?
The default CRF 23 provides excellent quality for most uses. Lower values (18-20) are better for professional work; higher values (28-35) produce smaller files for sharing.
Can I convert WebM with VP9 to MP4?
Yes, this tool handles all WebM files regardless of the codec used (VP8, VP9, or AV1). The output is always H.264/AAC MP4.
Privacy & Security
This tool uses FFmpeg compiled to WebAssembly (WASM). The WASM binary (~25MB) is downloaded from a CDN on first use and cached by your browser. All file processing happens locally on your device - your files are never uploaded to any server. This makes it safe for sensitive, private, or confidential media files. Large files may take longer to process depending on your device's CPU and available memory.