Compress a video
For getting a clip under an email or upload limit. You control exactly what is traded away — resolution, frame rate or compression — instead of a slider that hides it.
- Runs entirely in your browser
- Works offline
- No upload
- No sign-up
- No watermark
Loading the tool…
How it works
- Drop the video.
- Lower the resolution or raise the CRF; 720p at CRF 28 is a good starting point.
- Start, then check the reported before/after size.
Why nothing is uploaded
Every operation on this page is done by code running inside your browser tab, using the same engine that renders web pages. The file is read from disk into your tab’s memory, transformed there, and written back out as a download. It is never sent anywhere — not to us, not to a third party.
Verify it yourself
- Open your browser’s developer tools (F12) and select the Network tab.
- Load your file and run the tool.
- The only requests you will see are the tool’s own code and, once cached, none at all.
Frequently asked questions
What should I change first?
Resolution. Going from 4K to 1080p removes three quarters of the pixels before compression even starts, and on a phone screen the difference is invisible. Raising CRF is the second lever; lowering the frame rate is the last, because it changes how the motion feels.
Why is it slower than a desktop program?
Because it is FFmpeg compiled to WebAssembly rather than native code, and because a browser tab gets a fraction of your machine. This page is served with cross-origin isolation headers so ffmpeg can use several threads, which recovers most of the difference — but a native encoder will still win.
Is my video uploaded?
No. FFmpeg itself is compiled to WebAssembly and runs inside this tab; the file is read from disk into memory and the result is written back out. Nothing is transmitted, which is why a two-hour film will not work here — your device is doing all of it.