How to Convert PNG to ICO for Favicons and Windows Icons

To convert a PNG to ICO, open a browser-based converter such as UpperPix, drop in your PNG, select the ICO sizes you need (16×16, 32×32, 48×48, 64×64), and generate the file. The result is a single .ico containing multiple resolutions, which browsers and Windows pick from automatically. This works best when your source PNG is square, has a transparent background, and is at least 256×256 px so the largest size stays sharp.

What an ICO file actually is

An ICO is a container, not a single image. It holds several bitmap versions of the same icon at different pixel sizes, and the operating system or browser chooses the closest match for the context — a 16×16 tab icon, a 32×32 taskbar icon, a 48×48 or 64×64 desktop shortcut.

That is why a plain PNG renamed to .ico usually fails: the format is wrong, and there is only one resolution to scale from. A proper conversion re-samples your source into each size and packs them together.

Step-by-step: PNG to ICO in the browser

1. Prepare the source PNG. Use a square image, ideally 256×256 px or larger. Keep transparency if you want the icon to sit cleanly on any background. Crop away stray edges first — thin borders become muddy at 16×16.
2. Open the converter. On UpperPix, the ICO option sits alongside JPG, PNG, WebP, AVIF, BMP and SVG in the convert tool. Processing happens locally in the browser, so the file is not uploaded.
3. Drop the PNG in or click to browse.
4. Choose the ICO sizes to include. The tool offers 16×16, 32×32, 48×48 and 64×64. Select all four for a general-purpose favicon; a single 16×16 is enough only if you know the exact target.
5. Generate the ICO file and download it.

The expected result is one .ico file. You can verify it by checking the file size — a multi-size ICO is noticeably larger than a single 16×16 — or by opening it in an image viewer that reports embedded sizes.

Choosing sizes for each use case

If you only need a favicon and want to skip manual sizing, a dedicated favicon generator can produce a full package — UpperPix's favicon maker builds a downloadable .zip from text, an emoji, or an image, which is faster than assembling sizes by hand.

Transparency, shape, and sharpness

PNG's alpha channel carries over into the ICO, so a logo with a transparent background keeps clean edges. Two things break this in practice:

• Non-square source. The converter will fit or crop it, and the result looks stretched or clipped. Crop to a square before converting.
• Low resolution. A 64×64 PNG cannot produce a crisp 64×64 ICO, and upscaling a small source to 256×256 adds blur. Start from the largest clean version you have.

Fine detail — thin strokes, small text — disappears at 16×16. Design or pick an icon that still reads at that size, or accept that the smallest variant will look simplified.

Common problems and fixes

The icon looks blurry after conversion. The source was too small or not square. Re-export a 256×256+ square PNG and convert again.

The favicon does not update in the browser. Browsers cache favicons aggressively. Hard-refresh (Ctrl+F5 or Cmd+Shift+R), open the site in a private window, or clear the cache. This is a caching issue, not a conversion failure.

Windows still shows the old shortcut icon. Windows caches icon thumbnails. Rename the shortcut, move it, or rebuild the icon cache to force a refresh.

The ICO will not open or looks empty. The file may have been saved with the wrong extension or the conversion was interrupted. Regenerate and confirm the download completed.

Replacing a favicon or shortcut icon

For a website, place the .ico at the site root (commonly favicon.ico) or reference it explicitly in the page head:

<link rel="icon" href="/favicon.ico" sizes="any">

For a Windows shortcut, right-click the shortcut → Properties → Change Icon → Browse to your .ico file → select it → OK. If the old icon persists, see the caching fix above.

Both paths use the same file, so one well-built multi-size ICO covers web and desktop.