Sharpen Image
Sharpen Image — instantly, in your browser, with nothing uploaded.
Drag & drop your image here, or click to choose. Everything runs in your browser — nothing is uploaded.
This applies a genuine unsharp convolution kernel — not a contrast trick — so edges gain definition the way they do in a photo editor. Useful for slightly soft phone shots, scans and images that lost detail when they were resized down.
Frequently Asked Questions
How do I use the sharpen image tool?
Drop your image onto the box above, adjust the controls, and the preview updates as you drag. When it looks right, choose PNG, JPG or WEBP and press Download. Nothing is uploaded at any point.
Are my files uploaded to a server?
No. The file is decoded and re-encoded directly in your browser using JavaScript and WebAssembly, and never leaves your device. That is what makes it safe for private photos, client work and anything confidential, and it is why the tool keeps working with your network disconnected once the page has loaded.
Why does heavy sharpening look bad?
Sharpening exaggerates the difference between neighbouring pixels, so past a certain point it starts amplifying noise and drawing bright halos around edges. Keep it modest — sharpening can only emphasise detail that is already there, it cannot recover detail that was never captured.
Is there a limit or a watermark?
No limits, no watermark, no signup and no cost. Because the work happens on your own device there is no server bill to cover, so there is nothing to meter — the only real constraint is your device’s memory on very large files.
Does this work on Windows, Mac, iPhone and Android?
Yes. It runs in any modern browser on Windows, Mac, Linux, iPhone and Android with nothing to install and no account needed. Chrome, Edge, Firefox and Safari are all supported.