PNG to ICO
Make a favicon from a square PNG — never uploaded.
How it works
Three steps, and nothing leaves your device.
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1
Drop a square PNG in
512×512 or larger gives the best result at every size.
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2
Six sizes are rendered
16, 32, 48, 64, 128 and 256px, all inside one file.
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3
Download the .ico
Drop it at your site root as favicon.ico.
What actually goes into an .ico
- An ICO is a container, not a single picture. It holds several sizes at once and the operating system or browser picks whichever it needs — 16px in a browser tab, 32px in a taskbar, 256px in a large file listing. This builds all six from your one PNG.
- Start square and start large. A non-square source is squashed to fit. Something around 512×512 downscales cleanly into every size; starting from a 32×32 PNG means the larger entries are upscaled and soft.
- Detail disappears at 16 pixels. A full logo with a wordmark turns to mush at favicon size. The icons that work are a single letter, a monogram or one simple shape — design for the smallest size, not the largest.
- Transparency is kept. Each size is stored as PNG data inside the ICO, so an alpha channel comes across intact and the icon sits properly on both light and dark browser chrome.
- Where it goes. Put it at your site root as
favicon.icoand browsers will find it without any markup at all — the one asset that still works by convention alone.
Frequently asked questions
Which sizes are included?
16, 32, 48, 64, 128 and 256 pixels, all in a single .ico file.
Does my PNG have to be square?
It should be. A non-square image is squashed to fit each square size.
Is transparency kept?
Yes. Each size is stored as PNG data inside the icon.
Where do I put the file?
At the root of your site as favicon.ico. Browsers look there by default.