About compressing video
This tool compresses a video to reduce its file size. You pick a quality level and optionally lower the resolution, and download a smaller MP4. It re-encodes the video in your browser with ffmpeg in WebAssembly, so your file is never uploaded.
How Compress Video works
How to use it
- Drop or choose a video.
- Choose a quality level (higher = smaller) and optionally a max resolution.
- Compress and download.
How it works
Compression re-encodes the video with the H.264 codec at a chosen quality (CRF) — a higher number throws away more detail for a smaller file. Scaling down the resolution reduces size dramatically. It all runs locally with ffmpeg compiled to WebAssembly, and the result shows how much smaller it became.
Tips
The Recommended setting balances size and quality for most clips. For email or messaging limits, combine a smaller resolution with a higher compression level.
Common uses
- Reduce a video file size
- Fit a video under an upload limit
- Compress for email or chat
- Shrink a phone recording
- Make a video easier to share
- Lower the resolution
- Save storage space
- Compress an MP4
Frequently asked questions
How do I compress a video?
Drop it, choose a quality level and optional resolution, then compress and download.
Is my video uploaded?
No — compression runs in your browser with ffmpeg WebAssembly.
How much smaller will it be?
It depends on the settings; the tool shows the before and after sizes.
Why is it slow?
In-browser re-encoding is slower than native; shorter clips are quickest.
Will quality drop?
Higher compression trades some quality for size; the Recommended setting is balanced.
Why is the first run slow?
The engine (~32 MB) downloads once, then is cached.
What output format do I get?
A compressed MP4 (H.264).
Is it free?
Yes — completely free with no sign-up.