Image Upscaler
Enlarge an image 2×, 3× or 4× with Lanczos resampling and sharpening — no upload.
About this tool
Pick 2×, 3× or 4×, set the sharpening, press upscale: the image is resampled with the Lanczos filter print shops use and saved as PNG. Everything happens in your browser, capped at 4096 pixels on the long side.
What resampling can and can't do
Enlarging an image means inventing pixels between the ones you have, and the algorithm decides how. The browser's default is fast and blurry; nearest-neighbour is blocky; Lanczos fits a smooth curve through the neighbours and keeps edges crisp, which is why it is the choice for printing and why this tool uses it, plus an unsharp mask to counter the softness any interpolation adds. Honest framing: this is interpolation, not AI. An “AI upscaler” hallucinates plausible detail — sometimes right, sometimes a face that isn't quite the person — and needs a large model or a server. This tool never invents anything, which makes it right for logos, screenshots, scanned documents, diagrams and photos that need to print larger, and wrong for turning a thumbnail into a poster. For pixel art use the pixel art scaler, which keeps hard edges deliberately; to go the other way, the resizer; and What DPI you actually need for printing explains how big a print a given image can honestly support.
Frequently asked questions
Does it use AI?
No — Lanczos interpolation plus sharpening. It makes an image bigger and cleaner without inventing detail, so a small blurry photo becomes a larger blurry photo. AI upscalers guess detail; this one doesn't guess.
What is it good for?
Logos, icons, screenshots, scans and diagrams that need to be larger, and photos that print larger than their pixels would normally allow. Anything where a faithful enlargement beats an imaginative one.
Why is output capped at 4096 pixels?
Memory: a 4×4096 image is 16 million pixels, about the most a phone browser handles comfortably. Larger sources are scaled less than the factor and the page says so.
Is my image uploaded?
No — the resampling runs in your browser. A 2× enlargement of a phone photo takes a second or two.