Why do you need an ICO file?
ICO is the standard format for icons on Windows and for browser favicons. Unlike PNG or JPEG, an ICO file can contain multiple image sizes bundled into a single file. Windows picks the right size automatically depending on context: 16x16 for window title bars, 32x32 for the taskbar, and 256x256 for large icon views in Explorer.
For websites, a favicon.ico file in the root directory is still the most universally recognized favicon format. Modern browsers also accept PNG favicons, but the ICO format provides the broadest compatibility across all browsers and bookmark managers, including older versions of Internet Explorer and Firefox.
If you are developing a Windows desktop application, an ICO file is required for the app executable icon. Having all sizes bundled in one file ensures the icon looks sharp at every size Windows might display it.
For websites: place your favicon.ico in the root directory of your site, then add a link tag in your HTML head: <link rel="icon" href="/favicon.ico">.
Create your ICO file in three steps
The entire process happens in your browser. No server, no account. Always free.
Upload your image
Drag a PNG (preferably square, with transparency) onto the tool or click to browse. A preview appears right away.
Select sizes
Choose which icon sizes to include in the ICO file. For a favicon, 16, 32, and 48px are standard. For a Windows app, include up to 256px.
Download your ICO
Click Generate ICO and save the file. Upload it to your server root or include it in your application bundle.
Tips for creating great ICO files
Start with a square PNG
ICO files contain square images. A square PNG with transparency is the best source. Rectangles will be cropped or distorted.
Use high-resolution input
Start with at least a 256x256 pixel source image. The tool scales down cleanly; scaling up creates a blurry result.
Keep designs simple
Icons are displayed at very small sizes. Simple, bold shapes and clear silhouettes read much better than detailed illustrations at 16x16.
Include all standard sizes for Windows apps
For a Windows application icon, include 16, 32, 48, 64, 128, and 256px sizes. This covers all Windows display contexts.
Test your favicon in a browser
After uploading, clear your browser cache and reload your site to see the new favicon. Browsers cache favicons aggressively.
Frequently asked questions
Which sizes should I include in the ICO?
For a website favicon: 16, 32, and 48px are the essentials. For a Windows application: 16, 32, 48, 64, 128, and 256px covers all use cases.
What image format should I start with?
A square PNG with a transparent background gives the best results. The tool scales it precisely to each selected size.
Can I create a favicon.ico for my website?
Yes. Download the ICO file, name it favicon.ico, and upload it to the root directory of your web server. Then add a link tag in your HTML head section pointing to it.
Is my image private and secure?
Your images are processed securely and stay private. They are never shared or stored anywhere.