MP4 to WebM Converter
Convert MP4 video to WebM right in your browser. MP4 is the universal video format that plays on virtually every device, while WebM is an open, web-optimised format with efficient compression. Conversion uses your device's built-in video encoder where available, so it's fast — and because it runs locally, your video is never uploaded.
Drop a video here or click to browse
Converted on your device. Nothing is uploaded. Large files run best on desktop.
How to convert MP4 to WebM
- Drop your MP4 file into the box above, or click to browse.
- Choose WebM as the output format.
- Click “Convert to WebM”. Your device does the work — no upload.
- Download your WebM video. No watermark, no sign-up.
Frequently asked questions
Is this MP4 to WebM converter free?
Yes — completely free, no account and no watermark. The only limit is your device's memory and CPU/GPU, since it runs locally.
Are my videos uploaded?
No. Your MP4 video is processed entirely in your browser and never leaves your device.
Why is it faster than other converters?
Where your browser supports it, conversion uses the device's hardware video encoder (WebCodecs). If not, it falls back to a built-in software engine.
What size videos can I convert?
Short to medium clips work well. Very large or long videos use a lot of memory — a desktop browser is recommended.