Image upscaler
Choose a picture and an enlargement factor. The picture is grown in steps of at most 2 times with your browser's high-quality smoothing, then sharpened a little so edges do not look soft. This is classic interpolation: it makes the file bigger, it does not invent detail that was never there.
Runs in your browser: nothing you enter is sent anywhere.
How to use it
- Choose or drop a picture.
- Pick Enlarge by 2, 3 or 4 times.
- Adjust Sharpening while you watch the preview.
- Press Download enlarged image.
How it works
The picture is redrawn at up to twice its size, again and again, until the target size is reached; each redraw uses the browser’s high-quality smoothing. The result is then sharpened with an unsharp mask, which adds back a share of the difference between the picture and a blurred copy of it. The settings are the only thing you control: no model guesses what the missing detail might have looked like.
Example
A 1200 × 800 picture enlarged 3 times is made in two steps, 2400 × 1600 and then 3600 × 2400. The output is 3600 × 2400, about 8.6 million pixels.
Tips
- Start from the best copy you have; enlarging a picture that was already compressed hard also enlarges its artefacts.
- For print, check the pixel size you need first: the output size is shown above the preview.
Frequently asked questions
Does this add detail to a small picture?
No. It uses interpolation, which fills the new pixels with smooth blends of the old ones. The picture gets bigger and looks smoother than a plain stretch, but a blurry or tiny photo stays blurry. Programs that draw in new detail use trained models; this tool does not.
Why enlarge in steps?
One big jump with a smoothing filter gives softer edges than several small ones. The tool doubles the size as often as needed and makes the last step to the exact target size.
What is the sharpening for?
Enlarging softens edges a little. The sharpening is an unsharp mask applied after the enlargement; set it to 0 to switch it off or raise it if the result looks soft. Too much creates bright halos along edges.
How large can the result be?
Up to 16384 pixels on a side and 100 million pixels in all, which is a limit of browser canvases. The preview shows at most 900 pixels on the long side, the downloaded file is full size. The file keeps the format of the original.