Batch WebM to MP4 Converter
Convert WebM to MP4 online for free. 100% secure, fast, and private local file conversion directly in your browser. No software installation required.
Why convert WebM to MP4?
WebM is a royalty-free format that Chrome, Firefox, and Edge play beautifully, which is why so many videos downloaded from the web — short clips, tutorials, and even some courses — arrive as .webm files. The problem is everywhere else: Safari and iOS do not support WebM, many desktop editors and presentation tools refuse to import it, and social platforms frequently fail to preview it. Converting WebM to MP4 gives you the same content in the one format that plays almost anywhere.
WasmConvert converts WebM to MP4 entirely on your device, with no upload, so the clip stays private even if it is a download you would rather not re-send anywhere. The re-encode moves the video from VP8 or VP9 to H.264 and the audio from Opus or Vorbis to AAC, which is what makes it playable in Safari, iMovie, PowerPoint, and the rest. A quality slider lets you balance fidelity against output size, and there is no limit on file size, so large WebM files convert locally in one pass.
Common use cases
- Opening a WebM tutorial or clip on an iPhone, iPad, or any Safari-based device
- Importing web-downloaded WebM video into iMovie, Premiere, or PowerPoint presentations
- Uploading a WebM clip to a messenger, social platform, or course system that cannot preview it
How to convert WebM to MP4 (Step-by-step)
Select or drop your file
Click "Choose Files" or drag and drop your WebM file directly onto this page.
Set target format
Make sure the output format is set to MP4.
Local conversion
Click convert. Your file is processed entirely in your browser memory - no data is uploaded to our servers.
Save instantly
Once finished, your MP4 file is ready to download.
WebM is a royalty-free audiovisual format designed specifically for the web. Converting WebM to MP4 ensures your video will play on iOS and Safari devices.
MP4 is the most widely supported digital multimedia container format. It is universally compatible with all web browsers, smartphones, and media players.
Pro tips for WebM to MP4 conversion
- A WebM file can hold VP8 or VP9 video; both re-encode to H.264 in the MP4, which is what unlocks playback in Safari, iMovie, and PowerPoint — expect a similar file size if you keep the quality setting near the default.
- If the WebM contains an alpha channel (transparent video from OBS or online background removers), that transparency is lost in MP4, which has no alpha support — keep an alpha-capable WebM copy or use a green-screen workflow instead.
- WebM audio is usually Opus or Vorbis; the MP4 will carry AAC instead, which plays everywhere but is slightly larger than Opus at equal quality, so do not be surprised by a few extra megabytes.