Video tool · Free

Resize a Video to 4K (3840 x 2160)

Convert any video to 4K at 3840 x 2160, keeping the original aspect ratio. Free, in your browser.

Free to startIn your browserUp to 500 MB
How it works

Resize to 4K in 3 steps

1

Upload your video

Drag and drop a file, or click to browse. Files up to 500 MB.

2

4K is already selected

The resolution is pre-set to 4K (3840 x 2160). Pick another in the panel if you change your mind.

3

Resize and download

Create a free account to download the resized file, or keep editing in REQO.

When 4K is the right export

4K is four times the pixels of 1080p, which matters for large screens, for footage you plan to crop into later, and for anything being archived. It does not make a 1080p source sharper: upscaling can only stretch detail that is already there.

The honest use for a 4K export is a 4K source. If your recording came out of a phone or a camera at 2160p, exporting at 4K preserves it. If it came from a 1080p screen recording, you are quadrupling the file size for nothing.

ResolutionPixelsBest for
4K3840 x 2160Native 4K sources, big screens, archiving
1080p1920 x 1080The default for uploads and sharing
720p1280 x 720Email, chat apps, smaller files
480p854 x 480Hard size limits and rough previews
FAQ

resize to 4k: questions

Can I upscale a 1080p video to 4K?

You can export at 4K, but it will not add detail. The picture is stretched, the file gets roughly four times heavier, and on a big screen it looks softer than a native 4K source.

Why is my 4K file so large?

Four times the pixels needs several times the bitrate to look clean. If size is the problem, export 1080p or run the file through the compressor.

Does the aspect ratio change?

No. The source aspect ratio is preserved, so nothing is stretched or cut. To change the shape of the frame, use the crop tool instead.

Is resizing to 4K free?

Yes. Resize and preview for free, then create a free account to download.

Need more than resize to 4k?

REQO is a full browser video editor: record, edit by transcript, caption and export.