Convert PNG to ICO
One PNG in, one real multi-size favicon out — 16 to 256 pixels bundled in a single ICO, built entirely on your device.
Drop your image here
or
JPG, PNG, WebP, HEIC, SVG — any size, no upload
🔒 Files never leave your device — everything runs in your browser.
The usual reason to need an ICO: a favicon. Browsers, Windows shortcuts, and pinned sites all read the same decades-old ICO container, and the correct version carries SEVERAL sizes in one file — 16 and 32 pixels for browser tabs, 48 for Windows, up to 256 for high-DPI displays. Many free converters cheat here too: they stuff a single resized image into the container and call it done, which is why so many favicons look mushy in one place and jagged in another.
This tool builds the real thing: your PNG is resized to each standard favicon size and every one is bundled into a single ICO, with transparency preserved throughout. Non-square images are centered on a transparent square rather than stretched. Sizes larger than your source are skipped — an upscaled favicon helps nobody — but the 16/32/48 core that browsers and Windows require is always included.
How it works
- Drop your file
Any common format, any size. Nothing is uploaded — the tool runs in your browser.
- Choose quality or size
Pick a quality preset, set an exact KB target, or switch the output format — tuned for png to ico.
- Download
Your converted file is ready on your device — nothing to wait for, nothing to delete from a server.
Frequently asked questions
Which sizes end up inside the ICO?
The standard ladder — 16, 32, 48, 64, 128, and 256 pixels — capped at your source's own resolution, since upscaling adds blur, not detail. Every consumer picks the size it needs from the same file: browser tabs use 16 or 32, Windows uses 48, high-DPI surfaces take the rest.
Does transparency survive?
Yes. The entries inside the ICO are stored as PNGs, so the alpha channel carries through at every size — your icon keeps its cutout shape on tabs, desktops, and dark browser themes alike.
My logo isn't square — what happens?
It is centered on a transparent square canvas at each size, never stretched or cropped. That is the standard treatment for favicons; if you want the icon to fill the square completely, crop the source to a square first in any editor.
What size should my source PNG be for the best favicon?
256 pixels square or larger. That lets every size in the ladder be generated by downscaling, which keeps edges crisp. A large SVG logo also works — convert it here directly and the vector renders sharp at every step.
Is my file uploaded to a server?
No. ConvertUno runs entirely in your browser on your own device. Your file never leaves your computer or phone — there is no upload at all.
Is it really free, with no watermark?
Yes. Processing happens on your device, so serving you costs us almost nothing — no watermark, no account, no file-size limit, no daily quota.