ICO to ICNS
Convert a Windows ICO into a macOS .icns app icon with sizes from 16 to 1024 px, built in your browser.
How to convert ICO to ICNS
- Choose or drop an .ico file. Its images are read in your browser.
- Sizes up to the largest image in your ICO are selected. Add 512 or 1024 px for Retina slots if you need them.
- Download the ICNS and check it in the Finder and Dock previews.
Use the ICNS on a Mac
To change a folder or app icon, open the .icns in Preview, copy it, select the item in Finder, press ⌘ I, click the small icon at the top of the Info window and paste.
In an Electron project the file usually goes in build/icon.icns; Tauri uses icons/icon.icns.
ICO to ICNS questions
Why are 512 and 1024 px marked Enlarged?
An ICO holds at most 256 px, so those slots are scaled up from the largest image. They fill the Retina sizes so macOS does not stretch a small one, but they cannot add detail. For a sharp 1024 px icon, start from the original artwork, such as a large PNG or SVG.
Which images go into the ICNS?
16 and 32 px use Apple's classic RLE format with an 8-bit mask, which every macOS version reads. 64 px and larger are PNG, written for both the 1x and @2x slots. When your ICO already has a size, that artwork is reused instead of resizing another one. To change which sizes the ICO holds first, resize the ICO file.
Is transparency kept?
Yes, including soft edges. ICO images with 1-bit masks keep their hard edges.
Is my icon uploaded?
No. The ICO is decoded and the ICNS is assembled on your device. Up to 20 MB per file. Need website icons from the same artwork as well? Use the favicon generator.
Can I convert the ICNS back?
Yes, with ICNS to ICO. To see the images inside an ICO first, extract them as PNG. Starting from a bitmap? Convert BMP to ICO before this step. Need a scalable version of the icon too? Trace the ICO into an SVG.