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Build a Favicon ICO From Any Image

A proper .ico holds several sizes in one file, so the browser tab, the bookmark bar, and a Windows shortcut each get a version drawn for them.

Drop an image here or click to browse. Square images work best.

 

What an ICO File Is

The .ico format is a container. Inside it sit several complete images, and whatever displays the icon picks the size it needs: 16px in a browser tab, 32px on a bookmark bar, 48px in a Windows folder, 256px on a high-DPI desktop. Serve a single-size icon instead and everything but that one context gets a rescaled, slightly mushy version.

This builder redraws your image at each size you tick. Tick one size and you get one .ico; tick several and you get the combined multi-size favicon.ico plus a separate .ico for each size. Non-square sources are centered on a transparent square rather than stretched.

Strong

  • One file covers tabs, bookmarks, desktop shortcuts, and pinned sites.
  • Browsers request /favicon.ico by convention; it works with zero markup.
  • Transparency is preserved at every size.

Weak

  • Useless for anything except icons; it's not an image interchange format.
  • Detail dies at 16px, so complex art turns to noise (see below).
Simple bold mark rendered at 16 pixels, still legible
Good one bold shape, two colors: still legible rendered at real 16px tab size.
Detailed logo rendered at 16 pixels, illegible mush
Bad a detailed logo at the same 16px, exaggerated by blowing it back up: text and fine lines turn to mush. Squint at your logo; whatever survives belongs in the icon.

From logo to live favicon

  1. Start from a square image, 256px or larger (drop an SVG and it rasterizes).
  2. Keep 16, 32, and 48 ticked; add 256 if Windows desktop shortcuts matter.
  3. Build, download, and upload the file as /favicon.ico in your site root.