Convert to ICO, Free
Files convert instantly in your browser. 100% private, any file size, no account needed.
Drop your ICO file here
or click to browse. Any file size.
Conversion runs entirely in your browser. Your file never leaves your device.
How to convert to ICO
ICO is the format Windows uses for icons, and it is also the format browsers expect for favicon.ico files. An ICO file can contain multiple image sizes in a single file container, which is why browsers and operating systems can pick the most appropriate size depending on the context. A favicon at 16x16 is used in browser tabs; 32x32 is used in browser address bars; 48x48 is used in Windows Explorer; 256x256 is used for modern desktop shortcuts. A well-formed ICO file includes several of these sizes simultaneously.
This converter accepts any image file (PNG, JPEG, SVG, WebP) and produces an ICO file directly in your browser using WebAssembly. Your image never leaves your device. You can select which sizes to embed in the ICO container. For favicons, the standard recommendation is to include at least 16x16, 32x32, and optionally 48x48.
Upload the source image
Drop your source image onto the converter. A PNG with a transparent background produces the cleanest icon because ICO supports transparency. The source should ideally be at least 256x256 pixels for the converter to downsample cleanly.
Select sizes to embed
Choose which icon sizes to include in the ICO file. For a website favicon: 16x16 and 32x32 are essential. For a Windows desktop application: add 48x48 and 256x256.
Convert in browser
The converter resamples the source image to each selected size and packs them into the ICO container format. The process runs locally in WebAssembly with no server upload.
Deploy as favicon
Save the favicon.ico to your website's root directory. Reference it in your HTML: <link rel='icon' href='/favicon.ico'>. Modern browsers also support PNG favicons directly: <link rel='icon' type='image/png' href='/icon-32.png'>.
Frequently asked questions
Is an ICO file just a renamed PNG?
No. ICO is a distinct binary container format that can hold multiple images at different sizes and color depths. A renamed PNG will not work as an ICO. The converter generates a proper ICO binary structure.
Do I still need favicon.ico now that browsers support PNG favicons?
For maximum compatibility including IE11 and some older mobile browsers, yes. Modern browsers (Chrome, Firefox, Safari, Edge) support <link rel='icon' type='image/png'> and no longer require .ico. Placing favicon.ico in the root is still good practice because browsers request it automatically even without a HTML link tag.
Is my image uploaded to a server?
No. The conversion runs entirely in your browser using WebAssembly. Nothing is uploaded anywhere.
What is the 256x256 size in ICO used for?
Windows Vista and later use 256x256 PNG-compressed images inside ICO files for high-quality rendering on desktop shortcuts, taskbar icons at high DPI, and Start menu tiles. Including this size ensures crisp icons on modern Windows displays.
How do I create a round or shaped icon?
ICO uses a square canvas; the operating system applies corner rounding and masking based on its own UI conventions. Design your icon with a transparent background PNG, and the OS will handle the shaping. macOS, iOS, and Android each apply their own shape masks.