ICO to EXR Converter
Convert ICO to EXR in your browser. ICO files usually come from website favicons, Windows programs and installers; EXR is the better fit for visual effects, compositing and 3D render output. You get a ZIP-compressed OpenEXR with 16-bit half-float channels, the 8-bit sRGB values converted to linear light. Nothing is uploaded.
- Processed locally
- No upload, no wait
- No sign-up
- No watermark
Drop images here
or choose files · paste with Ctrl/⌘ V
ICO expected · other image formats also work
How to use ICO to EXR
- 1
Add your ICO files: drop them here, choose them, or paste from the clipboard.
- 2
There is nothing to tune: the EXR is written losslessly. Resizing and rotating are under More options if you need them.
- 3
Click Convert. Each file is decoded and encoded in a background thread on this device.
- 4
Download the .exr files one at a time or together as a ZIP.
Why use Aback Images for ico to exr
Where the EXR goes next
EXR opens in Nuke, Blender, Houdini, After Effects, DaVinci Resolve, Photoshop, Krita and OpenImageIO.
EXR next to ICO
Both sides are lossless, so the size depends on how well the EXR encoder handles this picture compared with the ICO's each size stored as a headerless BMP or as a complete PNG.
Written without a lossy pass
The EXR is written losslessly, so the pixels decoded from the ICO arrive unchanged.
Processed on your device
Your images are decoded, edited and encoded inside this browser tab by Web Workers. Nothing is uploaded to a server.
ICO vs EXR
What changes from ICO to EXR
Encoding: the ICO uses each size stored as a headerless BMP or as a complete PNG; EXR uses none, RLE, ZIP, PIZ, PXR24, B44 or DWA, chosen per file, and the download is a ZIP-compressed OpenEXR with 16-bit half-float channels, the 8-bit sRGB values converted to linear light.
Bit depth: 1 to 32 bits per pixel, set per size in the ICO; EXR allows 16-bit half or 32-bit floating point per channel, and the EXR written here has 16-bit half float per channel.
Colour: RGB or a palette, per image in the ICO; EXR supports scene-linear RGB, often ACEScg or linear Rec.709, written here as linear-light RGB.
Transparency: the ICO stores it as 8-bit alpha in 32-bit and PNG entries, or a 1-bit mask in old icons; the EXR keeps it as an A channel stored like any other channel.
Other images: the ICO can hold several sizes of the same picture, typically 16, 32, 48 and 256 px; only the main image is converted.
Metadata: the ICO can carry only a directory of the sizes inside, with no EXIF; EXR can carry named header attributes such as chromaticities, timecode and camera data, but nothing is copied across.
About ICO
ICO is a container that bundles several sizes of the same icon (16, 32, 48, 256 px) into one file. It is still the most compatible format for website favicons and Windows app icons.
An ICO starts with a 6-byte ICONDIR (type 1 for icons) and a 16-byte entry per image giving width, height, colour count and offset. Each image is either a BMP without its file header plus an AND mask, or a complete PNG.
ICO files usually come from website favicons, Windows programs and installers.
About EXR
OpenEXR is the high dynamic range format of film visual effects. It stores half or full floating-point channels in linear light, plus any extra render passes, and is the working format of compositing pipelines.
An EXR starts with the magic number 76 2F 31 01 and a version field, then a header of named, typed attributes (channels, compression, dataWindow, displayWindow) and a table of offsets to scanline or tile blocks.
When converting ICO to EXR makes sense
EXR is the better choice for visual effects, compositing and 3D render output, while ICO suits favicons and Windows icons.
EXR strengths: True high dynamic range in linear light; Any number of channels and render passes; Lossless compression options. Drawbacks to weigh: Needs tone mapping to look right on a normal screen; Very large files; No browser or phone support.
Limitations
- The largest image in the icon is the one converted; smaller sizes that were hand-tuned for 16 px are not carried over.
- No range is added: the EXR holds the 8-bit picture in linear light, and nothing in it is brighter than the original white.
- Compositing and 3D software read the EXR as linear light, the convention for the format, so it displays correctly there.
- The file holds colour and, when the image has transparency, an alpha channel; there are no extra render passes.
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Frequently asked questions
Does converting ICO to EXR lose quality?
EXR is written losslessly, so the pixels are stored exactly as decoded. Not carried over: any several sizes of the same picture.
Is transparency kept in the EXR?
Yes. ICO stores it as 8-bit alpha in 32-bit and PNG entries, or a 1-bit mask in old icons, and the EXR is written with an alpha channel, so transparent areas stay transparent.
Does saving as EXR add dynamic range?
No. The values come from an 8-bit image, converted to linear light so compositing software displays them correctly, but nothing brighter than the original white is invented. The file is ready to use as a plate or texture in an EXR pipeline.
Which apps open EXR files?
Nuke, Blender, Houdini, After Effects, DaVinci Resolve, Photoshop, Krita and OpenImageIO. It does not open in web browsers.
Are my images uploaded anywhere?
No. Processing happens inside your browser with WebAssembly and Web Workers. The site only downloads the app code and codecs; your files never leave your device. You can confirm this with the live upload counter on the tool, or in your browser's network panel.
Can I process many files at once?
Yes. Drop a whole selection or folder. Files are processed in parallel on several worker threads, each result can be downloaded on its own, and everything can be saved as one ZIP.
Is it free? Is there a file limit or watermark?
It is free with no account, no watermark and no daily limit. The only limit is your device's memory: very large images (over roughly 100 megapixels) may be refused to keep the tab from crashing.