PNG is a versatile lossless format with transparency support. PNG opens in most environments, but another format such as ICO may suit some uses better.
ICO is a container format for favicons and Windows icons. When you convert PNG to ICO, it can be used as an icon or favicon. See the comparison below for what changes.
This converter reads the file itself to confirm it is PNG, then converts it to ICO right in your browser. Your image is never uploaded.
PNG vs ICO: what's the difference?
| Item | PNG | ICO |
|---|---|---|
| Compression | Lossless | Lossless |
| Transparent background | Yes | Yes |
| Animation | No | No |
| Introduced | 1996 | 1985 |
| Support in programs and upload forms | nearly everywhere | moderate |
| Shown directly in browsers | Yes | Yes |
| Photo file size (JPG = 1) | about 3× | n/a |
What is PNG?
PNG (Portable Network Graphics) is a lossless format created in 1996 to avoid the patent problems around GIF. Because not a single pixel changes when you save and reopen it, it suits original artwork that goes through many edits.
What is ICO?
ICO is the format used for Windows icons and website favicons. Its distinguishing feature is that one file can hold several sizes, such as 16×16, 32×32 and 256×256.
What changes when you convert PNG to ICO
Pixel values are preserved exactly
PNG and ICO are both lossless, so there is no change in quality. Only the file structure, compatibility and size differ.
It is fitted into a square of at most 256×256
ICO is limited to 256×256. Larger images are scaled down with their aspect ratio kept, and images that aren't square are centered with the leftover area left transparent.
ICO has no quality setting
ICO is lossless, so the quality slider doesn't apply. Instead, when converting from PNG you can manage file size by resizing (exact width and height, or a percentage).
How the file size changes
ICO holds images of up to 256×256, so a large original shrinks a lot. If the image is already small, the difference is negligible.
ICO has narrower support than PNG
PNG support is nearly everywhere and ICO support is moderate. Check that the recipient can open ICO first, and if you're not sure, JPG or PNG is safer.
When to convert
- You're making a website favicon or a Windows shortcut icon
- You're preparing an image for typical ICO uses (website favicons, windows program icons)
- You want to tidy a PNG file into a format that's easier to edit or archive
PNG → ICO: practical tips
An image for a favicon works best when it's square. If the aspect ratio differs, it is centered and the leftover area is left transparent.
ICO is limited to 256×256. Larger images are scaled down with their aspect ratio kept. To stay recognizable at small sizes, avoid images with a lot of text and use a simple shape.
Current browsers also accept PNG favicons, but Windows shortcut icons and older environments still need .ico.