ICO Converter (Multi-Size Favicon)
Create a real multi-size .ico favicon from PNG, JPG or SVG in your browser, with 16, 32, 48, 64, 128 and 256 px icons stored as PNG inside one file.
Runs entirely in your browser. Your data is never uploaded.
What is ICO Converter?
The ICO Converter builds a Windows icon (.ico) file containing several sizes of your image, by default 16, 32, 48, 64, 128 and 256 px. Browsers and Windows pick the size that best fits each place, so the icon stays crisp in tabs, bookmarks, the taskbar and on the desktop. Non-square images can be padded or cropped to a square.
How to use ICO Converter
- Drop, choose or paste a square image, ideally at least 256×256 px (PNG with transparency or SVG work best).
- Tick the Sizes to include.
- If the image is not square, choose to fit it inside a square or crop a centered square, and whether the padding is transparent.
- Check the size previews, download
favicon.ico, and add the HTML snippet to your page’s<head>.
Example
40×20 PNG with the default sizes
ICO file starting with bytes 00 00 01 00, containing six PNG entries: 16, 32, 48, 64, 128 and 256 px (a warning notes that sizes above 40 px are upscaled)
When to use ICO Converter
Use it to create favicon.ico for a website or an icon for a Windows application or shortcut. Modern sites should also provide a PNG apple-touch-icon and, ideally, an SVG favicon. If you need compatibility with Windows XP, which cannot read PNG entries, use a desktop icon editor that writes BMP entries.
How ICO Converter works
Each selected size is rendered with high-quality stepwise downscaling and encoded as a 32-bit PNG. The tool then writes the ICO container itself: a 6-byte ICONDIR header, one 16-byte directory entry per size (width and height bytes, where 0 means 256, 32 bits per pixel, data length and offset) followed by the PNG data. PNG-compressed ICO entries are part of the format since Windows Vista and are supported by all current browsers.
Common Use Cases
- Generating favicon.ico for a new website from a logo PNG.
- Making an application icon with 16–256 px sizes for a Windows program.
- Turning an SVG logo into a favicon that looks sharp in browser tabs.
Security Note
Images are decoded, processed and encoded locally in your browser with the Canvas API. Nothing is uploaded to a server.
FAQs
Which sizes does a favicon need?
16 and 32 px cover browser tabs and bookmarks; 48 px is used by Windows; 64–256 px are used for shortcuts and high-DPI screens. Including all six is a safe default.
Is a PNG inside an ICO really valid?
Yes. Since Windows Vista the ICO format allows each entry to be a PNG, and all modern browsers read such favicons.
How do I add it to my site?
Upload favicon.ico to your site root and add <link rel="icon" href="/favicon.ico" sizes="any"> to the page head.