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.

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.

PNG to ICO コンバーター

PNGをマルチサイズICO（16, 32, 48, 64px）に変換。Windowsとファビコン用。

100% in your browser. Your file never leaves your device.

PNG image

Sizes to include: 16×16 32×32 48×48 64×64

Drop a PNG image to begin.

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.

よくある質問

What is an ICO file?: 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.
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.

Last updated: 2026-05-20 By jarvisbox