Compress a video
Get a file under a size limit without handing it to a stranger's server.
Your file
Drop a file here, or click to choose
It stays on this device. Nothing is sent anywhere.
Settings
How to hit a size target
Two settings do almost all the work. Quality (-crf) controls how hard the encoder throws away detail, and resolution controls how much detail there is to begin with. Raising CRF by 6 roughly halves the file. Dropping 1080p to 720p roughly halves it again.
- Discord free tier, 10 MB: 720p, quality 30 to 32, audio 64 kbps. A 30 second clip fits comfortably.
- Email attachment, 25 MB: 720p, quality 28.
- Keep it looking good: stay at the source resolution and use quality 26. Expect roughly half the original size.
The result panel tells you the finished size and how much smaller it got, so you can nudge one setting and run it again.
Why re-encoding is the only real option
There is no lossless way to make a compressed video meaningfully smaller. Every honest compressor re-encodes, which means decoding every frame and encoding it again. Anything promising a 90% reduction with no quality change is either lowering the resolution behind your back or lying.
Why some clips refuse to shrink
Two videos of the same length and resolution can compress completely differently, and the reason is how much of the frame changes between frames. A codec stores one full picture and then, for everything after it, only the differences. A locked-off shot of someone talking gives it almost nothing to record. Gameplay, a handheld pan, confetti, rain or a scene transition gives it everything, because every pixel changed and there is no shortcut available.
So if a clip will not come down, check what is moving in it before pushing quality into the thirties. Fast-moving footage is exactly where a high CRF looks worst, which means the setting fails hardest on the material that needed it most. Trimming is the better lever there, and it is the one people leave alone.
Length is the factor nobody adjusts
File size scales directly with duration and there is nothing to offset it. Ten seconds of preamble on a forty second clip is a quarter of your entire budget spent on nothing. Cutting to the part that matters with cut video or trim before compressing will beat any combination of settings, and it produces a better clip regardless of size.
Resolution is the next strongest, because it works on area: 1080p to 720p removes more than half the pixels and typically halves the file. Quality is the finest of the three and the one to reach for last.
Working towards a target size
The reliable method is one change at a time. Run it, read the finished size in the result panel, adjust a single setting, run again. Changing two things at once means learning nothing from the result. Raising CRF by 6 roughly halves the file; dropping one resolution step roughly halves it again; halving the length halves it exactly.
If you are aiming at a specific service, the presets do the arithmetic already: Discord targets the 10 MB free tier, and email targets 25 MB with the base64 overhead accounted for. And if the output comes back larger than the input, the source was already compressed harder than your settings, so raise the quality number or drop the resolution rather than assuming something went wrong.
Common questions
How small can it get without looking bad?
Roughly half, reliably, at quality 26 to 28 with no resolution change. Beyond that, drop the resolution rather than pushing quality past 32, a sharp 720p file looks better than a smeared 1080p one.
Why is my compressed file bigger than the original?
The source was already compressed harder than your settings. Raise the quality number or lower the resolution and run it again.
Can I compress without losing any quality at all?
Not meaningfully. Quality 16 to 18 is close enough that you will not see the difference, but it will not save much space.