Convert WebM to MP4
Convert WebM videos to MP4 format instantly in your browser. MP4 plays on every device and platform — no more compatibility issues. No upload needed, 100% private.
Drag 'n' drop files here, or
click to select files
.webm
Drop your files and click Convert to get MP4
//when_to_use
When to Convert WebM to MP4
- Playing downloaded web videos on iPhone or iPad which don't support WebM natively
- Uploading screen recordings from Chrome (saved as WebM) to Instagram, TikTok, or LinkedIn
- Sending videos to clients who use Windows Media Player or QuickTime which can't play WebM
- Embedding videos in PowerPoint or Keynote presentations that require MP4 format
- Converting OBS recordings saved as WebM to MP4 for editing in Premiere Pro or DaVinci Resolve
//comparison
WEBM vs MP4
| Property | WEBM | MP4 |
|---|---|---|
| Container | WebM (Matroska-based) | MPEG-4 (.mp4) |
| Video codec | VP8 or VP9 | H.264 |
| Audio codec | Vorbis or Opus | AAC |
| Device support | Browsers, Android, Linux | Universal |
| Social media support | Limited | All platforms |
| File size | Typically smaller | Similar or slightly larger |
//how_it_works
How It Works
Drop your WebM video
Drag and drop or select a WebM file. First conversion loads the FFmpeg WASM engine (~30MB), which stays cached for subsequent conversions.
FFmpeg decodes VP8/VP9
FFmpeg WASM runs entirely in your browser. It reads the WebM container and decodes the VP8 or VP9 video stream along with Vorbis/Opus audio. Nothing is uploaded.
Re-encode as H.264 + AAC
Video is re-encoded to H.264 using libx264, audio to AAC. The +faststart flag moves metadata to the front for optimized web playback.
Download your MP4
Your universal MP4 is ready. It plays on every device — iPhones, Android, Smart TVs, media players, and all social media platforms.
// under the hood
WebM is a Matroska-based container using VP8/VP9 video and Vorbis/Opus audio codecs. Our converter uses FFmpeg WASM to decode the VP8/VP9 video stream and re-encode it as H.264 (libx264) with AAC audio in an MP4 container. The +faststart flag is applied to optimize for web streaming by placing the moov atom at the beginning of the file.
//faq
Frequently Asked Questions
- What is WebM format?
- WebM is an open video format developed by Google, commonly used on websites and in Chrome/Firefox browsers. It uses VP8 or VP9 video codecs with Vorbis or Opus audio. While great for web playback, many devices and apps don't support WebM natively.
- Why convert WebM to MP4?
- MP4 with H.264 is the universal video standard. It plays on every phone, tablet, TV, gaming console, and media player. Converting WebM to MP4 ensures your video works everywhere — including iPhones, Smart TVs, and social media platforms that reject WebM.
- Does the conversion lose quality?
- The video is re-encoded from VP8/VP9 to H.264 and audio from Vorbis/Opus to AAC. Quality is preserved at a high level using FFmpeg's default encoding settings. For most content, the difference is imperceptible.
- How long does conversion take?
- Conversion time depends on video length and your device's speed. A 1-minute video typically converts in 15-45 seconds. The FFmpeg engine loads once (~30MB) and stays cached for the session.
- Are my videos uploaded anywhere?
- No. All processing happens in your browser using FFmpeg compiled to WebAssembly. Your videos never leave your device. You can verify by disconnecting from the internet — conversion still works.