Resize a Video to 4K (3840 x 2160)
Convert any video to 4K at 3840 x 2160, keeping the original aspect ratio. A Pro export: free accounts get 1080p.
- 4K export is Pro
- Nothing to install
- Up to 1GB
Resize to 4K in 3 steps
Upload your video
Drag and drop the clip you want at 4K, or click to browse. Anything under 1GB.
4K is already selected
The resolution is pre-set to 4K (3840 x 2160). Pick another in the panel if you change your mind.
Resize and download
Create a free account to download the resized file.
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.
There are two honest reasons to export at 4K. The first is a 4K source: if your recording came out of a phone or a camera at 2160p, exporting at 4K preserves it. The second is YouTube, which encodes 4K uploads with a more efficient codec and a far higher bitrate than 1080p ones, so a 1080p video uploaded as 4K often looks cleaner there even to somebody watching at 1080p. YouTube does not document this; it is what creators consistently observe. Anywhere else, a 1080p source exported at 4K is four times the file for nothing.
If what you want is more detail rather than a bigger frame, that is a different job: AI upscaling, which rebuilds the picture instead of stretching it. REQO’s AI Upscale does that, as a Pro feature priced by length.
4K
1080p
720p
480p
| Resolution | Pixels | Best for |
|---|---|---|
| 4K | 3840 x 2160 | Native 4K sources, big screens, archiving |
| 1080p | 1920 x 1080 | The default for uploads and sharing |
| 720p | 1280 x 720 | Email, chat apps, smaller files |
| 480p | 854 x 480 | Hard size limits and rough previews |
Where the extra pixels actually show
Phone
Laptop, 13 to 16 inch
Desktop monitor, 27 inch+
TV, from the sofa
| Screen | Does 4K show | Roughly per minute |
|---|---|---|
| Phone | No | 300 MB |
| Laptop, 13 to 16 inch | Barely, up close | 300 MB |
| Desktop monitor, 27 inch+ | Yes | 300 MB |
| TV, from the sofa | Yes on 55 inch and up | 300 MB |
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.
What resolution is 4K exactly?
3840 x 2160 pixels, also called UHD, which is what TVs, monitors, phones and YouTube mean by 4K and what this exports. Cinema 4K (DCI) is slightly wider at 4096 x 2160 and is rarely what anybody needs outside a film workflow.
Can I turn a 720p video into 4K?
You can export it at 4K, but 4K has nine times the pixels of 720p, so the same detail is spread over a frame nine times larger and looks soft on a big screen. For YouTube it can still be worth it for the better encode; for anything else, 1080p is the sensible ceiling for a 720p source.
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?
4K is a Pro export. Free exports go up to 1080p, so on a free account the file comes back at 1080p. For a single file, a one-off $2 payment gets it at 4K with no badge and no subscription. You can resize and preview free either way.
Other presets
Everything else you can do here.
All resize video presets
Crop for a platform
Crop to a ratio
Compress for a destination
Compress a format
Rotate or flip
Change the frame rate
Change the speed
Transcribe a language
Extract audio from a format
Subtitles in another language
Convert a caption file
Need more than resize to 4k?
REQO is a full browser video editor: record, edit by transcript, caption and export.