CONVERT
FITS → ICO
Fast, secure FITS to ICO conversion. No registration required.
DRAG. DROP. DONE.
Upload any file and our engines will handle format detection automatically.
Max 100 MB · Free plan · No signup required
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Setup: FITS is a raster image format with its own balance of compression, colour depth, and software support. Goal: an interchangeable ICO. A FITS → ICO operation is one of the simplest image jobs there is: same pixel grid, different wrapper. What genuinely changes is how lossy the codec is, whether alpha survives, and how large the final file ends up. KaijuConverter picks safe defaults for each of those and lets you override them under Advanced. A quick refresher — FITS is a raster image format with its own balance of compression, colour depth, and software support. By contrast, ICO is the Windows icon container with multiple resolutions packed into one file.
FITS Astronomical Image
Source formatFITS (Flexible Image Transport System) is the standard digital file format in astronomy for storing images, tables, and metadata from telescopes and satellites. It supports multi-dimensional arrays and extensive header metadata for scientific observation records.
ICO Icon
Target formatICO is the icon file format used for favicons and Windows application icons. A single ICO file can contain multiple image sizes and color depths for different display contexts.
Why convert FITS to ICO
The real reason to move from FITS to ICO is almost never picture quality — both raster formats store essentially the same pixels. It is about the tools downstream: which editors open the file natively, which CMSes upload it without transcoding, which social platforms accept it. Picking ICO solves those edge cases at the cost of a short conversion step.
HOW TO CONVERT
FITS → ICO
Provide the FITS
Click or drag to upload. We accept a single FITS file per job, with an optional queue of additional images for batch mode.
Encode to ICO
The conversion decodes the FITS, resolves the colour space to sRGB and writes the ICO container around the pixel data.
Save the ICO
The download is streamed back over HTTPS. If you uploaded multiple files, a ZIP with all ICO outputs is produced instead.
Common Use Cases
Document embeds
Word, Google Docs and Pages embed ICO with correct aspect ratio; FITS may appear as a broken image icon.
Printer-friendly export
Consumer and office printers drive ICO through their print spoolers with no additional drivers.
Presentation slides
PowerPoint and Keynote treat ICO as a first-class citizen; FITS may need manual re-insertion per slide.
Online form uploads
Identity verification, job applications and legal forms often list ICO as the only accepted image format.
Quality & Compatibility
FITS-to-ICO conversion does not change the visible content. Quality is capped by the FITS decode; re-encoding a lossy source at high quality cannot recover detail that was already discarded. For archival masters, keep the original FITS alongside the ICO copy.
Tips for Best Results
- Large FITS files may look identical to small ICO files for photographic content; pick quality based on end use, not headline megapixels.
- For print, export ICO at 300 DPI minimum and check that the colour profile embedded matches the print shop specification.
- Batch-convert related FITS images in one pass so they share identical encoder settings and look consistent side-by-side.
Frequently Asked Questions
Frequently Asked Questions
It depends on the codecs involved. If both FITS and ICO are lossy, the pixels are re-encoded and a small amount of detail is discarded — invisible at default quality settings on photographs. If ICO is lossless (PNG, TIFF, BMP) the output keeps every pixel of the decoded FITS exactly, but cannot recover detail that FITS had already compressed away.
Often yes, especially when ICO is lossless. FITS tuned for efficient web delivery will usually produce smaller files than ICO's default settings. If file size matters, drop the quality in Advanced or pick a more compressed target format instead.
KaijuConverter uploads over HTTPS, processes the image in an isolated container and deletes both the source and the output within two hours. No account is required, file contents are never logged, and we do not use uploads to train any model. For confidential material, the paid plan includes a data-processing agreement.
Secure & Private Conversion
Your files are encrypted during transfer, processed in isolated containers, and automatically deleted within 2 hours. We never read, share, or store your data.