How to use
- Upload a PNG — square and at least 256×256 gives the sharpest result.
- Tick the sizes you want in the file. 16/32/48 px is the safe default; add larger sizes for high-DPI displays.
- Click Convert to ICO to build the multi-resolution icon.
- Download the
.icoand place it at your site root (asfavicon.ico) or use it as a Windows icon.
What is an ICO file
An .ico is a container that holds several icon images at once. When a browser needs a favicon, it reads the directory inside the file and picks the size that best fits where it’s showing the icon — a 16 px tab, a 32 px bookmark, or a larger high-DPI slot. Bundling multiple sizes means the icon always looks crisp instead of being scaled from a single bitmap.
Choosing sizes
- 16 px — browser tabs and address bars.
- 32 px — taskbar, bookmarks, and standard-DPI shortcuts.
- 48 px — Windows desktop and larger list views.
- 64 / 128 / 256 px — high-DPI displays and places the icon is shown big.
Including 16, 32, and 48 covers the vast majority of cases; add the larger entries when you want extra sharpness.
Transparency is preserved
Each size is embedded as a PNG inside the .ico, which keeps full 32-bit alpha transparency. Soft edges and transparent corners come through exactly as they look in your source image.
Private by design
The conversion happens entirely in your browser — the PNG is drawn to a canvas at each size and the .ico is assembled in memory. Your image is never uploaded, so it’s safe for confidential logos and brand assets.