WEBM to MP4 Video Converter
Drop your WEBM files — the MP4 video is generated in your browser in seconds. Multiple files at once, no upload on the fast path.
9,214+ video files converted
This tool turns your video into MP4 entirely in the browser. The universal video container — typically H.264 video plus AAC audio. Plays on virtually every device, browser, and app. You can convert several files at once, and because the fast path is local there is no upload step and nothing to clean up afterwards.
Looking to programmatically convert WEBM to MP4?
Same engine, available as a JSON API. Drop a file or URL via REST and get the converted video back — no browser, no UI, no rate limits on paid tiers.
Fast response on common video pairs
Webhook delivery for batch jobs
Dozens of video format pairs supported
WEBM vs MP4: how they compare
The numbers and capabilities at a glance, so you know what you're trading.
WebM
- Year released
- 2010
- Compression
- VP9 (lossy)
- Transparency
- Yes (alpha)
- Animation
- Yes (video)
- Browser support
- Modern browsers
- Best for
- Web embedding, open source
MP4
- Year released
- 2001
- Compression
- H.264 (lossy)
- Transparency
- No
- Animation
- Yes (video)
- Browser support
- Universal
- Best for
- Sharing & streaming everywhere
Real WEBM → MP4 file sizes
We ran fixed video clips through this exact converter so you can see the typical size impact before converting your own files.
| Video sample | WEBM size | MP4 size | Change |
|---|---|---|---|
| High motion | 157.7 KB | 301.3 KB | +91% larger |
| Complex detail | 174.6 KB | 369.4 KB | +112% larger |
Measured on synthetic 3s · 426×240 · 20 fps video clips with this converter on 2026-06-23. Real-world files vary with duration, resolution, codec and content.
Heads up before converting to MP4
What this specific conversion changes about your video.
Lossless when the codecs already fit
If your WEBM uses codecs MP4 accepts, we remux (rewrap) it losslessly and instantly. A codec change re-encodes, which recompresses slightly.
Best practices for MP4
Small choices that keep your output sounding right.
- Play the MP4 result back before deleting your original WEBM.
- Pick a preset (Web, Mobile, High quality) to balance size and quality for your MP4.
The importance of a good video conversion
Why getting WEBM → MP4 right matters more than you think.
Frequently asked
The basics everyone asks before dropping a track.
Convert WEBM to other formats
Convert other formats to MP4