Video Converter — MP4 to WebM Converter Online
Convert video files between MP4 (H.264/AAC) and WebM (VP9/Opus) formats. Full re-encode for maximum compatibility. All processing stays in your browser. 100% client-side — nothing leaves your browser.
How to Use the Video Converter
- Upload a video — drag an MP4 or WebM file onto the drop zone.
- Choose target format — select MP4 or WebM as the output.
- Select quality — High Quality, Balanced, or Small File preset.
- Convert — click Convert and wait for the process to complete.
- Download — save the converted file. Compare before/after sizes.
Format Comparison
MP4 (H.264/AAC): The most widely compatible video format. Plays on virtually every device and platform. Good compression-to-quality ratio.
WebM (VP9/Opus): Open, royalty-free format with excellent compression. VP9 typically achieves 30-50% smaller files than H.264 at the same quality, but encoding is slower.