Convert to ICO online

Free online converter for converting files to ICO.

How to convert files to ICO?

1
Upload your file
Click the 'Choose File' button or drag and drop your file into the upload area. Supported formats include PNG, JPG, WEBP and more.
2
Select the output format
Make sure ICO is selected as the conversion format. Adjust additional settings if needed.
3
Start the conversion process
Click the 'Convert' button and wait a few seconds. All conversions are performed on our servers.
4
Download the result
Once the process is complete, click the 'Download' button and save the file in ICO format.

Why choose our ICO converter?

We ensure quality, convenience, and support for all formats.

High-quality to ICO conversion
We guarantee precise to ICO file conversion without any loss of quality.
Support for multiple formats
You can convert your to ICO files from over 200 different formats, including images, documents, and more.
Compatible with all devices
Convert to ICO files from any device – whether it's a computer, tablet, or smartphone.
User-friendly interface
Our service is designed to make to ICO conversion easy for everyone in just a few simple steps.
Full data security
All files are transmitted and stored using advanced encryption technologies.
High-speed processing
Thanks to cloud technology, we ensure fast processing even for large to ICO files.

Convert to ICO: supported formats

Convert ICO to other formats

.ICO

ICO
Windows Icon
Data typeImage
MIME typeimage/vnd.microsoft.icon
DeveloperMicrosoft
Primary use casesApplication and file-type icons on Windows, desktop/shortcut icons, installer icons, website favicons

What is the ICO file format?

ICO is a Windows icon container format that can store multiple images (sizes and color depths) in one file, widely used for app icons and favicons.

ICO file characteristics

Data typeImage
MIME typeimage/vnd.microsoft.icon
CompressionNone for classic DIB/BMP entries; optional PNG compression for some entries (commonly for 256×256 icons)
Color depthCommonly 1/4/8/24/32 bpp per entry; transparency via 1-bit AND mask for many classic entries, or full alpha channel for 32bpp/PNG entries
Color spaceRGB (typically sRGB); may be palette-based or truecolor depending on entry
Transparency supportYes
Animation supportNo
MetadataVery limited; no standardized EXIF. ICO primarily stores icon images plus directory entries and optional extension blocks within embedded PNG data
Standard / SpecificationIANA: image/vnd.microsoft.icon; publicly published file format details referenced by IANA (Microsoft technical article “Icons in Win32”, 1995)
Typical file sizeUsually small (often a few KB to tens/hundreds of KB), but can grow when many sizes or large PNG entries are included
Year introduced1985

Advantages

The ICO file format offers several advantages that make it suitable for common use cases.

  • One file can include multiple icon sizes and color depths;
  • Very wide Windows support;
  • Common for favicons;
  • Supports transparency (mask and/or alpha);
  • Can embed PNG for high-detail icons

Limitations

The ICO file format has certain limitations that may affect its use in specific scenarios.

  • Designed for icons (small images) rather than general graphics;
  • Best results require shipping multiple sizes (e.g., 16×16, 32×32, 48×48, 256×256);
  • Transparency handling differs between classic mask-based and alpha-based entries

Compatibility

ICO images are widely supported and can be viewed on most devices and platforms.

  • Supported platforms: Windows; also supported by many browsers and image tools on macOS/Linux for viewing favicons and icons
  • Supported devices: PCs and web browsers (favicons/bookmarks), Windows apps and installers
  • Browser support: Yes
  • Backward compatibility: Yes

Security considerations

Treat ICO as untrusted input. Malformed headers (especially image-offset pointers) can trigger issues in poorly written parsers; keep viewers, browsers, and image libraries updated

License

Publicly documented format; no known licensing restrictions for use

ICO (Windows Icon) is a container format used primarily on Microsoft Windows for application, file-type, and shortcut icons. A single .ico file can include multiple raster images at different sizes and color depths. Icon images may be stored as classic Windows DIB/BMP data (with optional AND/XOR masks for transparency) or as PNG images (commonly used for 256×256 icons in newer Windows versions).