offlinewebtools.com — free, watermark-free browser tools that stay on your device with nothing uploading to our servers

WebM to MP4 Converter

Convert WebM videos to MP4 format for maximum compatibility across devices and platforms.

Free to use, no watermarks, runs in your browser—nothing uploads to our servers

Source file

Files are processed locally in your browser using WebAssembly.

Saved FFmpeg presets (stored locally)

Saved presets

Preset name

Quality (CRF)

Lower = better quality (0-51, default: 23)

Video Bitrate

Target bitrate (e.g., 500k, 1000k, 2000k)

MP4 has better compatibility with mobile devices, video editing software, and older media players.

There may be slight quality loss since you are re-encoding. Use higher quality settings (18-23) for better results.

MP4 with H.264 is generally less efficient than VP9, so the file may be slightly larger at the same quality level.

Report a bug

If this tool misbehaves, share a quick summary so we can investigate. We include the tool URL automatically—no need to copy and paste.