How to view a .CAL file online
No app, no account, no upload.
Open your .CAL
Drag a .CAL file onto the viewer, paste one with Ctrl+V, or choose it from your device.
View and inspect
Zoom in close, pan around, rotate or flip it, and read the exact color of any pixel.
Save a copy
Download it as PNG, JPG or WEBP with your rotation applied, at the quality you choose.
What is a .CAL file?
Everything worth knowing about CALS Raster Image (Type 1).
A CAL file is a CALS Type 1 raster image - a black-and-white scanned engineering drawing or technical document created under the U.S. DoD CALS program using CCITT Group 4 compression. To open one, use XnView, IrfanView, or ImageMagick. The easiest fix is to convert it to a Group 4 TIFF or PDF, which is lossless.
Programs that open .CAL files
- Windows
- IrfanView, ImageMagick, AutoCAD / Autodesk raster tools, XnView MP / XnView Classic
- macOS
- ImageMagick, XnView MP
- Linux
- ImageMagick, GDAL (gdal_translate)
| Full name | CALS Raster Image (Type 1) |
|---|---|
| Developer | U.S. Department of Defense (CALS initiative) |
| First released | Late 1980s (U.S. DoD CALS initiative; MIL-STD-1840, MIL-R-28002 / MIL-PRF-28002) |
| Category | Images |
| MIME type | image/cals |
Related tools
More free tools for working with images.
Frequently asked questions
Is my .CAL file uploaded to a server?
No. The viewer decodes your .CAL file with your browser's own image engine. Closing the tab removes it completely.
How do I open PSD, TIFF, RAW or HEIC files?
HEIC and HEIF (iPhone photos) open right here — we decode them with libheif. PSD, TIFF, JPEG 2000, camera RAW, HDR and texture files have their own viewers, linked above; the Image Viewer sends you to the right one automatically.
What does the Photo details panel show?
The EXIF data your camera or phone saved in the photo: camera and lens, shutter speed, aperture, ISO, the date it was taken and, if location was on, where. Files you save from this viewer don't include this data, which is handy when you share photos.
Is there a file size limit?
There's no fixed limit; it depends on available memory. Very large images (over 40 megapixels) are previewed at reduced resolution so the viewer stays fast, but the reported dimensions are always the original ones.
How does the color picker work?
Point at any pixel to see its HEX and RGB value with a magnified view of the surrounding pixels. Click to copy the HEX code and save it to your palette.
Should I save as PNG, JPG or WEBP?
PNG keeps every pixel and transparency, which is best for screenshots and graphics. JPG makes photos small. WEBP is usually the smallest of all and works in every modern browser.
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