How to use it
- Drop in a square PNG, ideally 1024 × 1024 px, or an SVG.
- Seven sizes are generated and packed into one file.
- Download the .icns.
What goes inside
An ICNS file is Apple's icon container. This converter stores PNG images at 16, 32, 64, 128, 256, 512 and 1024 pixels, the sizes macOS uses for everything from menu bars to the Finder's largest view and Retina displays. PNG-based entries have been the standard since OS X Lion.
Who needs one
- Developers packaging Mac apps with Electron, Tauri, Qt or similar, whose build tools ask for an
.icns. - Anyone giving a folder, drive or script a custom icon in Finder.
Designing for macOS
Since macOS Big Sur, app icons follow a rounded-square shape with a little margin, drawn by the designer rather than applied by the system. If you want your icon to sit comfortably next to Apple's, design it on a 1024 canvas with the rounded square roughly 824 pixels across and a soft shadow, and export that as the PNG.
PNG and ICNS compared
| PNG | ICNS | |
|---|---|---|
| First released | 1996 | 1998 |
| Compression | Lossless | Holds PNG or JPEG 2000 images |
| Transparency | Yes, including soft edges | Yes |
| Animation or pages | Only as APNG, rarely used | Many sizes in one file |
| Best for | Screenshots, graphics, text and transparency | macOS app icons |
| Support | Universal | macOS and icon tools |
Questions people ask
What size should my source image be?
1024 × 1024 px, or an SVG. Smaller images are enlarged for the biggest sizes and look soft.
Does ICNS support transparency?
Yes. Transparent areas stay transparent.
Can I convert an ICNS back to PNG?
Yes, with ICNS to PNG.