ICO is a Windows icon container that bundles several pixel sizes of the same icon. The browser or OS picks the right size for each display context.

Which sizes should I include?

16 and 32 are required for favicons. Add 48 and 64 for sharper Windows desktop icons on hi-DPI screens.

Is the upload private?

There is no upload. The PNG is read locally and the ICO is assembled in your browser with no network round-trip.

PNG to ICO Converter — Free, Multi-Size Icon Maker

How to convert PNG to ICO

Drop a square PNG (ideally 256×256 or larger) onto the upload area.
Choose which sizes you want embedded in the ICO.
Press Convert to ICO and download favicon.ico.

Common use cases

Website favicons: drop the downloaded file at /favicon.ico in your site root.
Windows desktop icons: right-click any shortcut → Properties → Change Icon → browse to your .ico.
Visual Studio / Electron apps: use an ICO as the application icon resource on Windows builds.

Frequently asked questions

Why not just rename my .png to .ico?

A rename produces an invalid container. Browsers and Windows look for the ICO header — a real ICO bundles one or more sized images in a specific format.

Does it support transparency?

Yes — each embedded size is encoded as a PNG stream inside the ICO, so the alpha channel is preserved.

What's the difference from ICO from PNG?

Same underlying converter — this page targets the "PNG to ICO" search phrase explicitly while ICO from PNG leans on the favicon use case.