# How to open a \*.cal file?

**URL:** <https://boards.straightdope.com/t/how-to-open-a-cal-file/290048>\
**Category:** Factual Questions\
**Created:** [February 14, 2005, 6:15pm UTC](https://boards.straightdope.com/t/how-to-open-a-cal-file/290048 "2005-02-14T18:15:46Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![Jinx](https://avatars.discourse-cdn.com/v4/letter/j/c6cbf5/32.png) [@Jinx](https://boards.straightdope.com/u/Jinx)\
**Post date:** [February 14, 2005, 6:15pm UTC](https://boards.straightdope.com/t/how-to-open-a-cal-file/290048/1 "2005-02-14T18:15:46Z")

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These files I have are possibly drawing files. A google search on file extensions led me to believe these were bitmap files, but I could not open with a common application such as Paint.

It could be a CALS raster group 1 image…whatever that means!  
Anyone have a clue what I need to open these files?

Thanx

- Jinx

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**Author:** ![ZipperJJ](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/zipperjj/32/211_2.png) [@ZipperJJ](https://boards.straightdope.com/u/ZipperJJ)\
**Post date:** [February 14, 2005, 6:22pm UTC](https://boards.straightdope.com/t/how-to-open-a-cal-file/290048/2 "2005-02-14T18:22:36Z")

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Looks like it’s sort of proprietary. Check out [this page](http://filext.com/detaillist.php?extdetail=cal&goButton=Go)

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**Author:** ![Fritz](https://avatars.discourse-cdn.com/v4/letter/f/c57346/32.png) [@Fritz](https://boards.straightdope.com/u/Fritz)\
**Post date:** [February 14, 2005, 7:25pm UTC](https://boards.straightdope.com/t/how-to-open-a-cal-file/290048/3 "2005-02-14T19:25:43Z")

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Where did this file come from or what generated it?

The \*.cal files that I am familiar with are Calibration files - files used to store calibration values for certain equipment. If this is what it is, you should be able to use Notepad or Wordpad to view it. Double-click on the file and select Notepad or Wordpad to open with - make sure you _uncheck_ “Always use the selected program to open files of this type.”  
If, after opening it, you see any readable text of any sort, chances are it’s a calibration file.

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**Author:** ![SpaceCop](https://avatars.discourse-cdn.com/v4/letter/s/91b2a8/32.png) [@SpaceCop](https://boards.straightdope.com/u/SpaceCop)\
**Post date:** [February 15, 2005, 4:26am UTC](https://boards.straightdope.com/t/how-to-open-a-cal-file/290048/4 "2005-02-15T04:26:10Z")

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I’ve opened .cal files using MicroStation. Microstation is a CADD program similar to AutoCADD. You can’t open them directly, you need to reference them into a file. AutoCADD probably has a similar procedure to view them.  
Are they on a CD? If so, it may have a view program on it. That’s the only way I’ve ever seen them.

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**Author:** ![DarrenS](https://avatars.discourse-cdn.com/v4/letter/d/977dab/32.png) [@DarrenS](https://boards.straightdope.com/u/DarrenS)\
**Post date:** [February 15, 2005, 7:25am UTC](https://boards.straightdope.com/t/how-to-open-a-cal-file/290048/5 "2005-02-15T07:25:33Z")

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Another thing that might give you a clue - try running [this](http://www.sysinternals.com/ntw2k/source/misc.shtml#strings) utility on one of the files to see if there are any readable strings. You’ll need to do it from the Command Prompt.

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**Author:** ![RumMunkey](https://avatars.discourse-cdn.com/v4/letter/r/b19c9b/32.png) [@RumMunkey](https://boards.straightdope.com/u/RumMunkey)\
**Post date:** [February 15, 2005, 11:34am UTC](https://boards.straightdope.com/t/how-to-open-a-cal-file/290048/6 "2005-02-15T11:34:58Z")

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Doesn’t Apple’s calendar application use the “.cal” extension as well?