{
 "id": "icon-file-format",
 "name": "Icon file format",
 "category": "image",
 "identifiers": {
  "extensions": [
   "ico"
  ],
  "mime": [
   "image/vnd.microsoft.icon",
   "image/x-icon"
  ],
  "puid": [
   "x-fmt/418"
  ],
  "wikidata": [
   "Q729366"
  ],
  "magic": [
   {
    "offset": 0,
    "hex": "00000100",
    "notes": "Icon file format"
   }
  ],
  "uti": [
   "com.microsoft.ico"
  ],
  "signatures": [
   {
    "name": "Icon file format",
    "sequences": [
     {
      "position": "bof",
      "offset": 0,
      "pattern": "00000100[01:09]00{3}00[00:01]00{1}00{3}00*000028000000{2}0000{2}00000100[01:20]0000000000"
     }
    ]
   }
  ]
 },
 "status": "writable",
 "summary": "This is an outline record only, and requires further details, research or authentication to provide information that will enable users to further understand the format and to assess digital preservation risks associated with it if appropriate. If you are able to help by supplying any additional information concerning this entry, please return to the main PRONOM page and select ‘Add an Entry’.",
 "tools": [
  {
   "name": "ImageMagick",
   "url": "https://imagemagick.org",
   "license": "ImageMagick License",
   "open_source": true,
   "reads": true,
   "writes": true
  },
  {
   "name": "ABViewer",
   "url": "https://cadsofttools.com/products/abviewer/",
   "reads": true,
   "writes": false
  },
  {
   "name": "Abydos",
   "url": "https://www.wikidata.org/wiki/Q133445760",
   "reads": true,
   "writes": false,
   "license": "GNU Lesser General Public License",
   "open_source": true
  },
  {
   "name": "ACD FotoCanvas Lite",
   "url": "https://www.wikidata.org/wiki/Q116994901",
   "reads": true,
   "writes": false
  },
  {
   "name": "ACDSee",
   "url": "https://www.acdsee.com",
   "reads": true,
   "writes": false,
   "license": "proprietary license"
  },
  {
   "name": "ACDSee 5",
   "url": "https://www.wikidata.org/wiki/Q116957642",
   "reads": true,
   "writes": false
  },
  {
   "name": "Acorn Image Editor",
   "url": "http://www.flyingmeat.com/acorn",
   "reads": true,
   "writes": true
  },
  {
   "name": "Adobe Captivate",
   "url": "http://www.adobe.com/products/captivate/",
   "reads": true,
   "writes": false
  },
  {
   "name": "Adobe Premiere Pro",
   "url": "http://adobe.com/products/premiere",
   "reads": true,
   "writes": false,
   "license": "proprietary license"
  },
  {
   "name": "ArchiCAD",
   "url": "https://www.graphisoft.com/plans-and-products/archicad",
   "reads": true,
   "writes": false,
   "license": "proprietary license"
  },
  {
   "name": "Aseprite",
   "url": "https://aseprite.org",
   "reads": true,
   "writes": true,
   "license": "proprietary license"
  },
  {
   "name": "CoffeeCup Software",
   "url": "https://www.wikidata.org/wiki/Q109284794",
   "reads": true,
   "writes": false
  },
  {
   "name": "Converseen",
   "url": "https://converseen.fasterland.net/",
   "reads": true,
   "writes": false,
   "license": "GNU General Public License, version 3.0",
   "open_source": true
  },
  {
   "name": "CorelDRAW Graphics Suite",
   "url": "https://www.wikidata.org/wiki/Q5788503",
   "reads": true,
   "writes": false
  },
  {
   "name": "Fast Picture Viewer",
   "url": "http://www.fastpictureviewer.com",
   "reads": true,
   "writes": false
  },
  {
   "name": "FastStone Image Viewer 5.2",
   "url": "https://www.wikidata.org/wiki/Q112767622",
   "reads": true,
   "writes": false
  },
  {
   "name": "GIMP",
   "url": "https://gimp.org",
   "reads": true,
   "writes": true,
   "license": "GNU General Public License, version 3.0",
   "open_source": true
  },
  {
   "name": "Graphic Workshop",
   "url": "http://www.mindworkshop.com/gwspro.html",
   "reads": true,
   "writes": false
  },
  {
   "name": "Hijaak Digital Photo Studio",
   "url": "https://www.wikidata.org/wiki/Q117814372",
   "reads": true,
   "writes": true
  },
  {
   "name": "imageio",
   "url": "http://imageio.github.io/",
   "reads": true,
   "writes": false,
   "license": "2-clause BSD License",
   "open_source": true
  },
  {
   "name": "IrfanView",
   "url": "https://www.irfanview.com/",
   "reads": true,
   "writes": true,
   "license": "freeware"
  },
  {
   "name": "Mathematica",
   "url": "https://www.wolfram.com/mathematica/",
   "reads": true,
   "writes": true,
   "license": "proprietary license"
  },
  {
   "name": "Microangelo Toolset",
   "url": "http://microangelo.us",
   "reads": true,
   "writes": false
  },
  {
   "name": "Microsoft Developer Studio",
   "url": "https://www.wikidata.org/wiki/Q116940555",
   "reads": false,
   "writes": true
  },
  {
   "name": "Microsoft Expression Media 2",
   "url": "https://www.wikidata.org/wiki/Q116877843",
   "reads": true,
   "writes": false
  },
  {
   "name": "Microsoft Paint",
   "url": "https://microsoft.com/windows/paint",
   "reads": true,
   "writes": true,
   "license": "proprietary license"
  },
  {
   "name": "Microsoft Photos",
   "url": "https://www.wikidata.org/wiki/Q26328552",
   "reads": true,
   "writes": false,
   "license": "Microsoft end-user license agreement"
  },
  {
   "name": "Microsoft Visual Studio 2005 Team Suite",
   "url": "https://www.wikidata.org/wiki/Q118586938",
   "reads": false,
   "writes": true
  },
  {
   "name": "OpenImageIO",
   "url": "http://www.openimageio.org",
   "reads": true,
   "writes": false,
   "license": "BSD licenses",
   "open_source": true
  },
  {
   "name": "Paint 3D",
   "url": "https://www.wikidata.org/wiki/Q29576170",
   "reads": true,
   "writes": false
  },
  {
   "name": "Photopea",
   "url": "https://www.photopea.com/",
   "reads": true,
   "writes": true
  },
  {
   "name": "PhotoRec",
   "url": "http://www.cgsecurity.org/wiki/PhotoRec",
   "reads": true,
   "writes": false,
   "license": "GNU General Public License",
   "open_source": true
  },
  {
   "name": "PhotoWorks 2.41",
   "url": "https://www.wikidata.org/wiki/Q116924176",
   "reads": true,
   "writes": false
  },
  {
   "name": "PhpThumb",
   "url": "http://phpthumb.sourceforge.net/",
   "reads": false,
   "writes": true,
   "license": "GNU General Public License",
   "open_source": true
  },
  {
   "name": "PicaJet",
   "url": "http://picajet.com/",
   "reads": true,
   "writes": false,
   "license": "freeware"
  },
  {
   "name": "Pixen",
   "url": "http://pixenapp.com",
   "reads": true,
   "writes": false,
   "license": "MIT License",
   "open_source": true
  },
  {
   "name": "Q122522973",
   "url": "https://www.wikidata.org/wiki/Q122522973",
   "reads": true,
   "writes": false
  },
  {
   "name": "Q130252332",
   "url": "https://sorairolake.github.io/qrtool/",
   "reads": true,
   "writes": false,
   "license": "Apache Software License 2.0 / Creative Commons Attribution 4.0 International / MIT License",
   "open_source": true
  },
  {
   "name": "Q141647655",
   "url": "https://getartcraft.com/apps/photocraft",
   "reads": true,
   "writes": true,
   "license": "Apache Software License 2.0 / MIT License",
   "open_source": true
  },
  {
   "name": "Q847465",
   "url": "https://ffmpeg.org",
   "reads": false,
   "writes": true,
   "license": "GNU Lesser General Public License, version 2.1 or later",
   "open_source": true
  },
  {
   "name": "Riptide Photo Studio",
   "url": "https://www.wikidata.org/wiki/Q116949403",
   "reads": true,
   "writes": true
  },
  {
   "name": "Snagit 8",
   "url": "https://www.wikidata.org/wiki/Q119488269",
   "reads": true,
   "writes": true
  },
  {
   "name": "VideoStudio X7",
   "url": "https://www.wikidata.org/wiki/Q113644652",
   "reads": true,
   "writes": false
  },
  {
   "name": "Zoner Photo Studio",
   "url": "http://www.zoner.com",
   "reads": true,
   "writes": true
  }
 ],
 "projects": [
  {
   "name": "File Formats Wiki",
   "url": "http://fileformats.archiveteam.org/wiki/ICO",
   "kind": "wiki"
  },
  {
   "name": "Kaitai Struct: ico",
   "url": "https://formats.kaitai.io/ico/",
   "kind": "grammar",
   "license": "CC0-1.0"
  },
  {
   "name": "PRONOM x-fmt/418",
   "url": "https://www.nationalarchives.gov.uk/PRONOM/x-fmt/418",
   "kind": "format-doc"
  },
  {
   "name": "Wikidata Q729366",
   "url": "https://www.wikidata.org/wiki/Q729366",
   "kind": "wiki"
  }
 ],
 "provenance": {
  "sources": [
   "converters",
   "ffw",
   "kaitai",
   "pronom",
   "wikidata"
  ]
 },
 "updated": "2026-10-24",
 "parsers": [
  {
   "engine": "kaitai",
   "url": "https://github.com/kaitai-io/kaitai_struct_formats/blob/master/image/ico.ksy",
   "license": "CC0-1.0"
  }
 ],
 "conversions": [
  {
   "to": "portable-network-graphics",
   "tool": "ImageMagick",
   "command": "convert in.ico out.png",
   "fidelity": "lossless",
   "losses": "Pixels kept; some metadata, colour profiles or layers may be dropped.",
   "url": "https://imagemagick.org"
  },
  {
   "to": "tagged-image-file-format",
   "tool": "ImageMagick",
   "command": "convert in.ico out.tif",
   "fidelity": "lossless",
   "losses": "Pixels kept; some metadata, colour profiles or layers may be dropped.",
   "url": "https://imagemagick.org"
  },
  {
   "to": "jpeg-file-interchange-format-1-02",
   "tool": "ImageMagick",
   "command": "convert in.ico out.jpg",
   "fidelity": "lossy",
   "losses": "Lossy compression.",
   "url": "https://imagemagick.org"
  },
  {
   "to": "webp",
   "tool": "ImageMagick",
   "command": "convert in.ico out.webp",
   "fidelity": "lossy",
   "losses": "Lossy compression.",
   "url": "https://imagemagick.org"
  },
  {
   "to": "gif",
   "tool": "ImageMagick",
   "command": "convert in.ico out.gif",
   "fidelity": "lossy",
   "losses": "Reduced to 256 colours.",
   "url": "https://imagemagick.org"
  }
 ],
 "aliases": [],
 "structure": [],
 "samples": [],
 "claims": [],
 "verification": []
}