WebM to MP4 Offline Converter

Convert WebM videos to MP4 format completely offline in your browser

No Upload 100% Private Free

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Drop your WebM videos here

or click to select WebM files

Conversion Settings

Video Quality

Output Resolution

Fast mode (prioritize speed over compression)

Perfect for WebM Screen Recordings

Screen Recordings

Convert WebM screen recordings from Chrome and other browsers to MP4.

Easy Sharing

Share your videos on any platform, device, or social media without issues.

Size Optimization

Reduce file sizes while maintaining quality for easier storage and sharing.

MP4 Works Everywhere

Android Devices

Windows PCs

Web Browsers

Smart TVs

Social Media

Game Consoles

Email Attachments

Cloud Storage

Technical Details

Accepts .webm files, the format of browser screen recordings, OBS captures and many web downloads. You can add several at once.
Video is re-encoded to H.264 at CRF 18, 23 or 28 (high, medium or low quality) and audio is converted to AAC, the combination every MP4 player supports.
Optionally downscale to 1080p, 720p or 480p (16:9 frame sizes), or keep the original resolution.
Fast mode uses the x264 "fast" preset for quicker conversion; turning it off uses "medium" for slightly smaller files.

Frequently Asked Questions

Why won't my WebM file open on my iPhone or in my editor?

WebM usually holds VP8/VP9 video and Opus or Vorbis audio, which many Apple apps and older video editors do not accept. H.264/AAC MP4 opens almost everywhere.

Is the conversion lossless?

No. The video is re-encoded. At the high-quality setting (CRF 18) the difference is very hard to see; the low setting makes smaller files with visible softening.