Image to ICO

What an ICO file is, and why it holds many sizes

The ICO format is the Windows and browser favicon container. A single .ico file can bundle several square images at different pixel sizes, and the operating system or browser picks the right one for the context: 16x16 for the browser tab and address bar, 32x32 for the task bar, 48x48 for a desktop shortcut, and 64, 128 or 256 for high-DPI displays and the app launcher.

This tool lets you tick which sizes to bundle. Available sizes are 16, 32, 48, 64, 128 and 256 pixels. Three quick presets select favicon (16 and 32), standard (16, 32, 48, 64) and all sizes (16 through 256). Each size is encoded as a PNG inside the container, which is the modern, sharp Windows Vista-and-later icon format.

• Sizes: 16, 32, 48, 64, 128, 256 px (tick any combination).
• Presets: favicon [16,32], standard [16,32,48,64], all [16,32,48,64,128,256].
• Each layer is a PNG, so transparent edges survive.
• Recommended input: a square, transparent PNG; max file 10 MB.

The three resize modes

When a source image is not square, the resize-mode dropdown decides how it becomes a square icon. Contain keeps the whole picture proportionally and centres it with empty (transparent) space around it. Cover fills the square by scaling to cover and cropping the overhang from the centre, which is the recommended choice for a tight icon. Stretch forces the picture to fill the square exactly, distorting non-square sources.

Because a logo or mascot usually needs to fill the frame, cover is the safest default; contain is the choice when the whole object must remain visible (for example a tall product silhouette).

Step by step and how to deploy the favicon

For a favicon, the 16 and 32 set is enough for most browsers; add 48 and 64 if you also target a Windows app or folder icon. If your source needs trimming to a square first, use crop; if it needs a transparent background first, cut it out with the background remover.

1. Upload a PNG, JPG or WebP (square transparent PNG works best; up to 10 MB).
2. Tick the sizes you want, or click a preset (favicon / standard / all).
3. Choose contain, cover or stretch resize mode.
4. Press generate ICO; a multi-size preview grid shows each layer.
5. Download the .ico and place it at your site root, or reference it with link rel=icon in your HTML head.

Why transparent PNG input matters, and privacy

Because every layer inside the ICO is rendered as a PNG, any transparency in the source is preserved in the icon. A source with a solid rectangular background turns into an icon with that background colour filling the square, which is why a cut-out, transparent PNG is recommended. The maximum bundled size is 256 pixels; there is no 512 or 1024 layer because the ICO spec caps the largest icon at 256, and adding more would just bloat the file without a target that uses it.

The generation happens entirely in the browser: each size is drawn to its own canvas, encoded as a PNG blob, and assembled into the .ico container locally. The original upload is never sent to a server, so logos and brand marks stay on your machine while you build the favicon. If you also need a standalone PNG of the icon at one size, the converter or resizer can export that separately.

• Transparent input preserves see-through edges in the icon.
• Maximum layer is 256 px; no larger sizes exist in the ICO format.
• Each layer is a PNG, so modern Windows renders it sharply.
• Assembly is local; the source upload is never uploaded.

Build a Multi-Size Favicon (.ico) From Any Image

Browsers and operating systems request an icon at several sizes, from the 16 by 16 pixel tab icon up to larger taskbar and shortcut tiles. PixlReady packs the sizes you select into one multi-resolution .ico file in your browser, scaling a square source image with a centered, aspect-ratio-preserving fit so logos are never stretched.

Start with a square PNG at least 256 by 256 pixels for the cleanest result, choose the sizes to include, and download a single favicon.ico ready to reference in your HTML. Conversion is local and adds no watermark.

Tips for best results

• Use a simple, high-contrast logo; tiny 16 by 16 sizes hide fine detail.
• Include 16, 32 and 48 at minimum, and 128/256 for modern launchers.
• Keep padding around the mark so it does not touch the icon edges.
• Also export a PNG and an apple-touch-icon for broader device support.

Common use cases

• Website browser-tab favicons
• Windows app and shortcut icons
• Bookmark and home-screen tiles
• Converting a square logo into a universally compatible icon file

Frequently Asked Questions