Compress a video
Make a video file smaller without uploading it anywhere. Re-encodes at a higher compression ratio in your browser, typically cutting size by 40–70%.
Your file is processed entirely in this browser tab. It is never uploaded, stored or seen by anyone.
To compress a video, drop it into the converter above. The file is re-encoded to H.264 at a Constant Rate Factor of 30 and scaled to a maximum of 1280 pixels wide, which typically reduces file size by 40–70% with modest visible quality loss. Everything happens on your device.
How it works
- Choose your file
Drag a file onto the converter, or click to browse. Nothing is uploaded — the file is read directly by your browser.
- Convert to Compress
Press Convert. FFmpeg runs as WebAssembly inside the tab and shows real progress as it works.
- Download the result
When it finishes, download the Compress file. It is created in your browser's memory and never sent anywhere.
Your file never leaves your device — conversion runs entirely in this browser tab.
About Compress
There are only three ways to make a video file smaller: reduce the resolution, reduce the bitrate, or reduce the length. This tool does the first two — capping width at 1280 pixels and raising the Constant Rate Factor from the default 23 to 30.
CRF is an inverted quality scale: lower numbers mean higher quality and larger files. Moving from 23 to 30 is a substantial step that typically halves the file size. On detailed footage the difference is visible if you look for it; on screen recordings, talking heads and most phone video it largely is not.
If the result is still too large, the most effective remaining lever is length. Trimming thirty seconds off a clip saves more than any encoder setting will.
| Codec | H.264 (AVC) + AAC |
|---|---|
| Container | MPEG-4 Part 14 |
| Typical bitrate | 0.8–3 Mbps at 720p |
| Compatibility | Universal |
| Best for | Email attachments, upload limits, storage |
Limits you should know about
Because conversion happens on your device rather than on a server, the ceiling is your browser's memory rather than our disk space. Files under 50MB work reliably everywhere. Desktop browsers stretch to roughly 200MB; mobile browsers, and iOS Safari in particular, cut out closer to 40MB.
Speed is the other trade. Running FFmpeg through WebAssembly is 5–10× slower than a desktop app, so a conversion that takes thirty seconds in a desktop application can take several minutes here. The converter shows a real estimate before it starts, and the tab has to stay open while it runs.
If your file is beyond those limits, trim it first, or use a desktop application such as HandBrake or FFmpeg directly — neither has a size ceiling.
Common questions
How much smaller will my file get?
Typically 40–70% smaller, depending on the source. Footage that was already heavily compressed shrinks less; high-bitrate camera or screen-recording output shrinks a great deal.
Will compressing lose quality?
Yes — compression is lossy by definition. The settings here are chosen to keep the loss modest on typical footage. Fast motion and fine detail suffer most; static shots and screen recordings suffer least.
Why is my video also smaller in dimensions?
Anything wider than 1280 pixels is scaled down, because resolution is one of the two biggest levers on file size. Video already narrower than 1280 is left at its original dimensions.