Convert
Convert MP4 to WEBM
Free, in your browser, with no watermark and no signup. Both are video files; this changes how the video is packaged and encoded.
Why you have a MP4 file
This is the one that runs the other way, and it is almost always for a website. WEBM with VP9 is meaningfully smaller than an equivalent MP4 at the same visual quality, which matters when the video is a background loop or a hero element that has to load fast.
What the conversion actually does
The H.264 video is re-encoded to VP9 and the AAC audio to Opus, inside a WEBM container. The result is typically smaller for the same perceived quality.
Worth knowing first
Only do this for the web. WEBM support outside browsers is patchy, so it is the wrong choice for anything you need to hand to a person, an editor, or a social platform.
How to convert MP4 to WEBM
- 01
Add your MP4 file
Drop it in, or pick it from your device. Free uploads go up to 1 GB per file.
- 02
Choose WEBM
Pick the output format from the list. Queue several files of the same type to batch them.
- 03
Download
Watch progress live, then download the result. No watermark, on any plan.
Other conversions
Frequently asked
How do I convert MP4 to WEBM for free?
Open the GrumpTools File Converter, add your MP4 file, choose WEBM as the output and download the result. It runs in the browser, output is never watermarked, and free uploads go up to 1 GB per file.
Does converting MP4 to WEBM reduce quality?
Only do this for the web. WEBM support outside browsers is patchy, so it is the wrong choice for anything you need to hand to a person, an editor, or a social platform.
Can I convert several MP4 files at once?
Yes. Queue multiple files of the same type and convert them in one batch, then download them individually or all at once.