Convert PNG to ICO

What is an ICO file?

ICO is the Windows icon format, also used by browsers for the favicon, the small image shown in the tab, in bookmarks and in your history. What makes it special: a single .ico file contains several images of different sizes. Windows shows the 16 × 16 version in lists and on the taskbar, the 32 and 48 for medium icons, and the 256 for large icons in File Explorer; the browser picks 16 or 32 depending on how sharp the screen is. That's why renaming a .png file to .ico isn't enough: a real ICO starts with a header that lists the sizes it contains. This tool writes that file properly, with each size stored as PNG, the format supported by Windows since Vista and by every current browser.

Create a favicon for your website

Start with a square, simple logo, then download the favicon pack. It contains favicon.ico (16, 32 and 48 pixels), apple-touch-icon.png (180 × 180, the icon used when someone adds your site to an iPhone home screen), icon-192.png and icon-512.png (for Android and web apps), the site.webmanifest file that declares them, and the HTML lines to copy. Put these files at the root of your website and paste the lines into the head tag of your pages. Website builders such as WordPress, Shopify, Wix or Squarespace usually just ask for a square PNG image: use icon-512.png in that case. Browsers keep the old favicon in memory for a long time: after a change, reload the page with Ctrl+F5 (Cmd+Shift+R on a Mac) or wait a little.

Change a folder or shortcut icon in Windows

For a folder, right-click it and choose Properties, then the Customize tab, the "Change Icon…" button, and Browse to pick your .ico file. For a shortcut, go to Properties, the Shortcut tab, then the "Change Icon…" button. Keep the .ico file in a folder that won't move: if it's moved or deleted, Windows goes back to the default icon. For an icon that stays sharp at every File Explorer view size (small, medium, large and extra large icons), check every size from 16 to 256 pixels with the "Windows" preset.

Make an icon that's readable, even at 16 pixels

A 16 × 16 icon has only 256 pixels: fine details, text and very thin outlines disappear. Go for a simple, high-contrast shape that fills the whole square, like an initial or a symbol, rather than a full logo with its tagline. Check the preview in both the light tab and the dark tab: a black logo on a transparent background becomes invisible in dark mode, and a background color can save it. If your image isn't square, choose between "Crop to square", which keeps the center, and "Whole image + padding", which adds transparent or colored edges. An SVG file gives the sharpest result, because it is redrawn before being scaled down to each size.