JPG, PNG or WebP, up to 50 MB. or drop a file here.
Free: 3 images a day per IP, no signup. Past that, see pricing.
Upscale a photo to 4K
3840x2160 is a 2x enlargement of a 1920x1080 photo, and that is the whole trick. Drop one in, pick 2x, and get the larger file back.
What 4K actually is
4K is a screen size with a precise definition: 3840x2160 pixels. The name comes from the width, which is a little under four thousand pixels. For enlarging a photo the useful part is the arithmetic: 3840 is exactly twice 1920 and 2160 is exactly twice 1080, so a 4K frame is a 2x enlargement of a 1920x1080 photo.
That is the whole trick, and there is no separate 4K mode hiding behind it. You pick 2x, and a 1920x1080 original becomes 3840x2160. What changes between the free tier and Pro is the size of the file each one accepts, not the factor: the enlargement is the same either way.
Why a 4x of a small image is not magic
An upscaler adds pixels; it does not add information. The model reads the pixels the file actually contains and predicts the ones in between, which is why a doubled 1080p photo can read as a real 4K photograph while a 4x of a 500x400 thumbnail is a bigger file and not a sharper one. 500x400 becomes 2000x1600, and every extra pixel is a guess made from the same small amount of detail.
So start from the largest copy you have. If a messaging app already shrank the photo, the detail it discarded does not come back, whichever factor you choose.
What the free tier covers, and what Pro changes
The free tier is the same tool with tighter caps and no account: input up to 2 MP, output up to 8 MP, and 3 upscales a day per IP. That fits a 2x of a 1600x1200 camera file, which lands at 3200x2400.
A 1080p original is 2,073,600 pixels, a little over the free input limit, and doubling it gives 8,294,400 output pixels, over the free output cap, so both go through Pro. Pro raises the input to 25 MP and the output to 64 MP, with 100 credits a month for $9: a 2x upscale costs 1 credit and a 4x upscale costs 2 credits. The pricing page lists the subscription and the one-time credit packs.
What you can upload
Accepted inputs are JPG, PNG, and WebP up to 50 MB each, and the result comes back as a PNG at exactly the dimensions you asked for. An animated file is refused rather than reduced to its first frame.
Uploads and results are private, served over short-lived signed links, and deleted automatically 1 hour after the upscale. The privacy page states the window for each path.
4K upscaling questions
What does a 4K upscaler do?
It enlarges an image to 4K dimensions. 4K is 3840x2160 pixels, and this tool reaches it with a 2x upscale of a 1920x1080 photo, with the pixels in between filled in by an AI model rather than stretched.
Can I turn a small image into a real 4K photo?
You can turn it into a file at 3840x2160 or larger, but the pixels are predicted rather than recorded. A smaller source gives the model less to work from, so the result is larger and softer than a real 4K capture. Use the largest version you have.
Is it free?
The free tier needs no account and no card: 3 upscales a day per IP, input up to 2 MP and output up to 8 MP. A 1080p original is a little over the free input limit, so it goes through Pro. The pricing page has the paid options.
Which image types can I upload?
JPG, PNG, and WebP up to 50 MB each. The download is a PNG at exactly the enlarged dimensions.
How do the credits work?
Pro is $9 a month for 100 credits a month. A 2x upscale costs 1 credit and a 4x upscale costs 2 credits, so the larger factor is charged for the extra work.
What happens to my images?
They are stored privately, delivered over short-lived signed links, and deleted automatically 1 hour after the upscale.