What Are ICO and favicon
Open any website and the small icon on the browser tab is the favicon. It is usually a .ico file, though PNG is also used. The favicon is the "face" of a website — users rely on it to quickly identify your site among many tabs.
Why the ICO Format Is Needed
Although modern browsers support PNG as a favicon, the ICO format still has irreplaceable advantages:
- Best compatibility: Old browsers and Windows desktop shortcuts only recognize ICO
- Multi-size packaging: A single ICO file can contain multiple sizes like 16x16, 32x32, and 48x48, and the system picks the right one automatically
- Bookmarks and PWA icons: Some cases still require ICO
DocsAll Image to ICO Tool
Use the Image to ICO Tool to generate one quickly:
- Prepare a square source image (256x256 or larger PNG recommended)
- Open the ICO Converter Tool and upload the source image
- The tool generates a multi-size ICO automatically
- Download the .ico file
How to Configure a favicon
Basic Configuration
Place favicon.ico in the website root directory and the browser will detect it automatically. You can also explicitly declare it in the HTML head with a link tag, setting the rel attribute to icon and the href to favicon.ico.
Multi-Device Adaptation
Modern websites should configure multiple sizes at the same time:
- favicon.ico: default, placed in the root directory
- apple-touch-icon.png (180x180): used when iOS adds to home screen
- icon.png (192x192, 512x512): for PWA
Source Image Design Tips
- Use PNG: Supports transparent backgrounds; ICO converted from PNG looks better
- Square: 16x16 and 32x32 are display sizes; a larger source image scales down better
- Keep it simple: Complex patterns become a blur at small sizes — use simple shapes and brand colors
- Transparent background: Avoids a white block and blends into the browser tab
Common Issues
favicon Not Updating
Browser caching is stubborn. If the favicon does not update after a change, force refresh (Ctrl+F5) or add a version parameter to the path, like favicon.ico?v=2.
Icon Looks Blurry
The source image is too small or a non-square got stretched. Regenerate with a square PNG of 256x256 or larger.
A clear favicon makes a website look more professional. The ICO tool gets it done in a few minutes — don't leave your tab empty.