ICO Icon Generator
Click to upload, or drag an image here
Drop an image or click to pick one — a multi-size .ico is built right in your browser
About ICO Icon Generator
Upload one image, tick a few sizes, and you get a single .ico file holding several resolutions — Windows and browsers pick whichever fits.
Why multiple sizes matter
The taskbar, desktop, Start menu and browser tab all ask for different sizes. Ship only 256x256 and Windows downsamples it into mush at 16x16; ship only 16x16 and it looks blurry on a high-DPI screen. 16, 32 and 48 is the usual trio; add 64, 128 and 256 when you want it sharp everywhere.
Crop or pad
For non-square images the default is a centred square crop, which is what most icons do. Pick "Fit inside" to keep the whole picture; the leftover space can be filled with a colour or left transparent.
Transparency
Every size is stored as PNG inside the ICO, so the alpha channel survives. The padding colour only matters in the "Fit inside" mode.
Frequently asked questions
How big is the .ico?
With all six sizes ticked it is roughly 1.3x the source PNG. For a website favicon 16/32/48 is plenty and usually stays under 100 KB.
Why is the 256 entry written as 0 in the header?
The width field is a single byte, so the spec stores 256 as 0. That is the format, not a bug.
Can I use it as a website favicon?
Yes — name it favicon.ico, drop it in the site root and add a link rel="icon" tag in the head. Add a couple of PNGs if you also want dark-mode and mobile icons.
