Icon Converter
Turn any image into a multi-resolution Windows .ICO file. Pick the sizes you need, add rounded corners or a background, and download — all in your browser.
Creates a multi-size Windows .ICO · nothing is uploaded.
How to convert an image to ICO
- 1
Drop or browse an image (a square image works best).
- 2
Choose which icon sizes to include (16–256 px).
- 3
Optionally round the corners and fill a background color.
- 4
Download your multi-size .ico file.
About the Icon Converter
Windows apps and many favicons use the ICO format, which can pack several resolutions into one file. The icon converter turns any image into a multi-size .ico with optional rounded corners and a background, so your icon looks crisp everywhere from a 16px taskbar to a 256px high-DPI display.
What an ICO file is for
The .ico format is the icon container Windows uses for application shortcuts, and it's still widely used for website favicons. Its useful trick is that a single .ico file can hold the same icon at several resolutions at once. The system then picks whichever size fits the moment — a tiny one for a browser tab or a crowded taskbar, a larger one for a desktop shortcut or a high-DPI display — so your icon looks sharp everywhere instead of being scaled from one fixed image.
Choosing which sizes to include
For most uses, 16, 32 and 48 px cover the everyday cases: browser tabs, bookmarks and the Windows desktop. Adding 256 px keeps the icon crisp on high-resolution screens and in large-icon views. Including a small spread like this is the whole point of the format — it's why a proper .ico beats dropping a single PNG and hoping the browser scales it well. Start from a square source image so nothing gets cropped or distorted when the sizes are generated.
Transparency and finishing touches
The entries in the .ico are PNG-compressed, which means they keep a real alpha channel — so if you leave the background fill off, transparent areas stay transparent and your icon sits cleanly on any backdrop. If you'd rather have a solid shape, turn the fill on and pick a color, and you can soften the look with rounded corners. The whole file is assembled in your browser, so your image is never uploaded. If you're building icons for a website specifically, the favicon generator produces the full set of files (including the .ico) plus the HTML to install them — see our favicon sizes guide for what a complete set looks like.
Frequently asked questions
What is an ICO file?
A Windows icon file that can hold several image sizes in one file — used for application icons and website favicons.
Which sizes should I include?
16, 32 and 48 px cover browser tabs and the desktop; add 256 px for high-DPI displays.
Can the icon have a transparent background?
Yes. Leave 'Fill background' off to keep transparency — the ICO uses PNG-compressed entries that support alpha.
Are my images uploaded to a server?
No. The ICO is built entirely in your browser; your image never leaves your device.
What's the difference between an ICO and a PNG?
A PNG is a single image at one size; an ICO can pack several sizes into one file so the system picks the best for each context. ICO is the format Windows and many favicons expect.
What image works best for an icon?
A square image with a simple, bold design works best, since it must stay legible at 16 px. Start from a larger image and let the tool generate the smaller sizes.