Convert MP4 to WebM
Select Files
Audio, Video and Image supported. Drag or click
Need to convert MP4 files to WebM for work, school, or a creative project? WeLoveConvert handles it instantly in your browser, completely free and without intrusive ads.
How It Works
Pick MP4 Files
Use the file picker or paste files from your clipboard. WeLoveConvert accepts every MP4 variant you throw at it.
Local Processing
The conversion engine runs in your browser using WebAssembly. Nothing is uploaded, nothing is logged, nothing leaves your machine.
Receive Your WebM Files
Each file is ready as soon as its conversion finishes. Download them one by one or as a single bundle.
About These Formats
When you convert MP4 to WebM you are swapping a general-purpose container (typically holding H.264 video plus AAC audio) for an open container built specifically around VP9 video and Opus audio. The result is a noticeably lighter file — usually 20% to 40% smaller at comparable visual quality — which is ideal for embedding video on a website, dropping a hero clip into a landing page, or serving short loops without burning through your CDN budget. Modern browsers like Chrome, Firefox, and Edge play WebM natively inside the HTML5 video tag, so there is no need for proprietary plugins or fallbacks. WeLoveConvert runs the FFmpeg encoder directly in your browser through WebAssembly, so the file never leaves your machine during the convert MP4 to WebM operation. For quality, target around 5 Mbps for 1080p clips and 2 Mbps for 720p, and lower the CRF value (try 30) if you want sharper detail. Two-pass encoding produces visibly cleaner motion at the same file size when you have time to spare.
Frequently Asked Questions
How do I convert MP4 to WebM?expand_more
Upload your files, confirm the conversion settings, and download your converted files. All processing happens in your browser — no server upload required.
Is this MP4 to WebM converter free?expand_more
Yes, completely free with no hidden fees. No sign-up required, no usage limits. All conversion happens in your browser.
Is it safe to convert MP4 to WebM online?expand_more
Your files never leave your device. All conversion happens locally in your browser using WebAssembly technology. We have zero access to your files.
Will I lose quality converting MP4 to WebM?expand_more
Quality depends on the target format and your settings. Lossless formats like PNG preserve original quality. For lossy formats like JPG, you can adjust the quality slider.
Can I convert multiple MP4 files at once?expand_more
Yes, you can convert multiple files at once. Simply drag all your files into the upload area or click to select them.
Common Issues
- infoiOS Safari (versions before 14) cannot play VP9 WebM — provide an MP4 fallback for iPhone users.
- infoAAC audio is re-encoded to Opus or Vorbis, which introduces a small but unavoidable quality loss.
- infoVP9 encoding is CPU-heavy and noticeably slower than H.264 — expect 3x to 5x longer processing time.
- infoSome legacy hardware decoders and smart TVs lack VP9 support and will refuse to play WebM files.