Convert MP4 to WebM
Convert MP4 videos into WebM, the open format built for the web. VP9 compression usually produces a smaller file at the same quality - ideal for websites and web apps. All processing stays on your device.
100% local - your file is never uploaded
Drop your MP4 file here, or click to select
Supports video/*,.mp4
How to convert MP4 to WebM
- 1
Drop your MP4 file into the box above, or click it to browse
- 2
Click "Convert MP4 to WebM" - processing runs locally in your browser
- 3
Watch the progress bar - nothing is uploaded, so there is no waiting on a network
- 4
Download your WebM file when the conversion finishes
Why convert MP4 to WebM?
If you are embedding video on a website, WebM with VP9 typically delivers the same visual quality as H.264 MP4 at a 20-40% smaller file size, which means faster page loads and lower bandwidth bills. It is also fully open and royalty-free, which some platforms and licenses require.
MP4
MP4 with H.264 is the universal interchange format - the file you get from cameras, phones, editors, and download sites.
WebM
WebM pairs VP9 video with Opus audio in an open container. Every modern browser plays it natively, and it is the recommended format for HTML5 video where bandwidth matters.
Frequently asked questions
When should I use WebM instead of MP4?
Use WebM for web embedding where file size and open licensing matter. Keep MP4 when the video must also play on Apple devices' native apps, older TVs, or be imported into desktop editors.
Why is VP9 encoding slower than expected?
VP9 spends more CPU time to achieve better compression - that is the trade-off that makes the files smaller. Since the work happens on your machine, speed scales with your hardware.
Will Safari play my WebM file?
Current Safari versions play WebM, but older iOS versions do not. For maximum reach, serve WebM with an MP4 fallback in your video element.
Need more options like other formats or quality settings? Use the full Video Converter tool.