What is an ICO file?
ICO stands for Windows icon. It was created by Microsoft and first released in 1985. An ICO file is a small container that can hold several sizes of the same icon, and since Windows Vista each size may be stored as an embedded PNG. The largest size an ICO can hold is 256 by 256 pixels.
| Type | image |
|---|---|
| Compression | Lossless |
| Colour | up to 32-bit colour with alpha, at most 256 by 256 pixels |
| Transparency | Yes |
| Animation | No |
| In a browser | shown by browsers as a favicon; opening one directly depends on the viewer |
| Common uses | website favicons and Windows program icons |
| MIME type | image/x-icon |
Which format should you convert ICO to?
- ICO to JPG for photos that must open everywhere and stay small.
- ICO to PNG for screenshots, logos and anything with transparency.
- ICO to PDF to print, or to attach as a document.
ICO is lossless, so converting it to a lossy format is where the file gets much smaller.
How to open an ICO file
Whether an ICO file opens with a double click depends on the device. Here is what works on each, without buying software:
| Windows | The Photos app opens common image formats. If ICO is not among them, a browser or a free viewer such as IrfanView will open it. |
|---|---|
| Mac | Preview opens most image formats and PDF files; Quick Look (press the space bar in Finder) shows a preview without opening an app. |
| iPhone and iPad | The Files app and Photos show common image types and PDF files. Other formats need an app, or converting here. |
| Android | Google Photos and Files by Google open common images and PDFs. Other formats need a viewer app, or converting here. |
| Web browser | ICO shown by browsers as a favicon; opening one directly depends on the viewer. |
Want the technical details? See what a .ico file is, with its MIME type, file signature and a viewer.
ICO compared with other image formats
How ICO stacks up against the formats people most often convert it to or from:
| Format | Compression | Transparency | Released | Best for |
|---|---|---|---|---|
| ICO | Lossless | Yes | 1985 | website favicons and Windows program icons |
| JPG | Lossy | No | 1992 | camera photos, web images and email attachments |
| PNG | Lossless | Yes | 1996 | screenshots, logos, diagrams and anything with transparency |
| WebP | Either | Yes | 2010 | images served by websites to save bandwidth |
| HEIC | Lossy | Yes | 2017 | photos taken on iPhones and iPads since iOS 11 |
How to use the ICO converter
- Choose the format you want in the Convert to menu.
- Drop your ICO files on the box, or press Choose ICO files. Several files can go in at once.
- Adjust the settings if you need to; the defaults suit most people.
- Press Convert and save each file with its Download button. Nothing is uploaded at any point.
Tips for converting ICO files without losing quality
ICO is lossless, so it is a good source for any conversion. Converting it to a lossy format is where the file gets much smaller, and converting it to another lossless format keeps every pixel.
- Choose by content: photos belong in JPG or WebP, while screenshots, logos and anything with transparency belong in PNG or WebP.
- Resize before you send. A modern phone photo is far wider than any screen, and scaling it to 1920 pixels removes most of the file size.
- Keep originals. Re-saving a JPG again and again slowly degrades it; convert from the original each time.
- Converting through the browser removes EXIF metadata such as GPS location, which is useful when sharing photos publicly.
Convert ICO files from the command line
Everything this page does can also be done in a terminal. The most common ICO conversion, to PNG, looks like this with ImageMagick:
magick input.ico output.pngChange the output extension to pick another format. The converter above runs the same kind of conversion inside your browser, so you get the result without installing anything.
ICO converter FAQ
What is an ICO file?
ICO stands for Windows icon, an image format created by Microsoft in 1985. An ICO file is a small container that can hold several sizes of the same icon, and since Windows Vista each size may be stored as an embedded PNG. The largest size an ICO can hold is 256 by 256 pixels.
How do I open an ICO file?
ICO shown by browsers as a favicon; opening one directly depends on the viewer. If the program you need will not open it, convert it to a more widely supported format above.
What is the most common ICO conversion?
ICO to PNG is the conversion people search for most. The image is decoded and written as a lossless 32-bit PNG.
Does converting ICO files here upload them?
No. Every conversion on this page runs inside your browser, so your ICO files never leave your device.
Is the ICO converter free?
Yes. There is no sign-up and no watermark, and no limit on how many ICO files you convert. The site is supported by advertising.
Can I convert ICO files on iPhone or Android?
Yes. Open this page in Safari on iPhone and iPad, or in Chrome on Android, choose your ICO files and download the results to your Downloads folder.
Can I convert several ICO files at once?
Yes. Drop as many as you like; they are converted one after another, each with its own download button.