4k → 1080p → 720p
4K to 1080p, and any other downscale
Downscaling is the fastest way to shrink a file. Going from 4K to 1080p removes three quarters of the pixels and usually cuts size by a similar margin.
Files are processed on your device · nothing is uploaded, stored or logged
How it works
Pick your file. The browser reads it straight from disk. There is no upload progress bar, because there is no upload.
The encoder loads once. A WebAssembly build of FFmpeg, around 30 MB, downloads the first time you use the site and stays cached afterwards.
Your processor does the work. Everything happens in this tab, at roughly half of real time on a modern laptop.
Save the result. The finished file is assembled in memory and handed to your downloads folder.
Downscaling beats compressing
A 4K frame holds four times as many pixels as a 1080p one. Dropping to 1080p therefore removes three quarters of the picture data before any compression even happens, which is a far bigger saving than turning a quality slider down.
It also costs less visibly. On a phone screen, and on most laptops, 4K and 1080p are close to indistinguishable — the extra resolution only shows on a large display viewed from nearby.
The aspect ratio is preserved automatically. A 4K video at 16:9 becomes 1920×1080; an unusual ratio keeps its proportions with the height calculated to match.
Upscaling is not offered, deliberately
Enlarging a video cannot add detail that was never captured. Tools that claim otherwise are either interpolating — which produces a soft, waxy image — or running models far too heavy for a browser tab. If you need 4K, you need to record in 4K.
Downscaling and compressing stack well together — after resizing, try compress video.
Common questions
Will 1080p look bad after 4K?
On a phone or laptop, no. On a large television viewed closely, you may notice slightly less fine detail.
How much smaller will the file be?
Typically 60 to 75 percent smaller going from 4K to 1080p, depending on content.
Can I upscale to 4K?
No, and no tool can do it honestly. Resolution cannot be invented after recording.
Do my files get uploaded?
No, everything runs on your machine.