ICO Maker
Turn any PNG, JPG, WebP, GIF, or BMP into a complete multi-resolution icon. Choose your sizes, pick ICO, ICNS, or ZIP, and download instantly — fully in your browser, nothing uploaded.
Make
What Is an ICO File?
An ICO file is a container format that stores one or more images at different sizes and color depths. Windows uses ICO files for application icons, cursors, and favicons. Rather than shipping a single image, an ICO bundles every resolution the OS might need — 16×16 for the taskbar, 32×32 for the desktop, 256×256 for large icons — so the right size is always available.
ICO vs PNG
| ICO | PNG | |
|---|---|---|
| Format | Container (multiple images) | Single image |
| Use case | App icons, favicons | Photos, graphics, web |
| Transparency | Yes (alpha or AND mask) | Yes (alpha channel) |
| Browser support | As favicon | Universal |
ICO Maker builds ICOs using a hybrid layout — BMP/DIB for smaller sizes and PNG for 256×256 and above — the exact structure Windows produces for maximum compatibility.
Common Use Cases
- App icons — Generate a Windows
.icofrom one source image with all standard sizes (16, 32, 48, 256) - Favicons — Build a multi-resolution
favicon.icofor your website - macOS app icons — Export an
.icnswith the sizes macOS expects (16–512) - PNG bundles — Package every size as individual PNGs inside a single ZIP
FAQ
Is my image uploaded to a server? No. Everything runs in your browser. The image is processed locally with JavaScript — nothing leaves your device.
Which output format should I pick? Choose ICO for Windows app icons and favicons, ICNS for macOS app icons, or ZIP if you just want a bundle of individual PNG files at each size.
Why does the ICO contain both PNG and BMP data? For best compatibility, ICO Maker stores sizes below 256×256 as BMP/DIB and sizes 256×256 and above as PNG. This hybrid layout is what Windows itself produces and ensures the icon renders correctly in Explorer and Photo Viewer.
Which sizes does ICNS support? ICNS supports 16, 32, 64, 128, 256, and 512 px. If you select only sizes outside this list (like 24 or 48), the ICNS export will warn you that no compatible size was selected.
Does it preserve transparency? Yes. Transparent regions in your source image are kept — as alpha in PNG entries and via the AND mask in BMP/DIB entries.
What's the difference between Smooth and Pixelated? Smooth (cubic) produces soft, high-quality scaling ideal for photos and gradients. Pixelated (nearest-neighbor) preserves hard edges, which is best for pixel art and low-color icons.
Need to extract layers from an existing .ico instead? Try the ICO Unpacker — the sibling tool that splits an .ico back into individual images.
Need more power on Windows? QuickICO is a native desktop compiler with Advanced Mode — per-layer image overrides, format control, and high-quality scaling. Free, with an optional Pro upgrade.