CAL File

What are CAL files and how to open them

Are you having problems opening a CAL file or are you simply curious about its contents? We're here to explain the properties of these files and provide you with software that can open or handle your CAL files.

What is a CAL file?

CAL files have multiple uses, and CALS Raster Bitmap Image is one of them. Read more about the other uses further down the page.

CALS Raster Bitmap Image File

We have not yet analyzed in detail what these files contain and what they are used for. We're working on it.

How to open CAL files

We have identified two CAL openers that are compatible with this specific type of CAL file.

Programs that open CALS Raster Bitmap Image files

Last updated: August 25, 2026

All known file formats using extension .CAL

While CALS Raster Bitmap Image File is a popular type of CAL-file, we know of 8 different uses of the .CAL file extension. Different software may use files with the same extension for different types of data.

Ease Calcform Spreadsheet File

We know that one CAL format is Ease Calcform Spreadsheet File. We have not yet analyzed in detail what these files contain and what they are used for. We're working on it.

While we have not verified the apps ourselves yet, our users have suggested ten different CAL openers which you will find listed below.

ExpressCalc Spreadsheet File

ExpressCalc Spreadsheet File stores a worksheet created by the ExpressCalc program (shareware for MS-DOS by Expressware Corporation) used to arrange, calculate, and format tabular data. It saves cells' values, formulas, formatting, and layout so that users can perform arithmetic, financial, or "what-if" analysis in DOS.

ExpressCalc itself writes these files. After saving a spreadsheet in version 4.0 of ExpressCalc, the file is later reopened and recalculated or edited using the same ExpressCalc software.

In technical terms, the file begins with the ASCII signature CALC4.0 followed by carriage return and line feed at the very start (bytes 43 41 4C 43 34 2E 30 0D 0A at offset zero).

Microsoft Project For DOS Calendar

We know that one CAL format is Microsoft Project For DOS Calendar. We have not yet analyzed in detail what these files contain and what they are used for. We're working on it.

PeachCalc Spreadsheet File

PeachCalc spreadsheet files store full worksheets created by Peachtree Software's PeachCalc module, part of the PeachText 5000 productivity suite. They contain all the rows, columns, formulas, and text labels that make up a saved spreadsheet - the kind of workspace used for financial modeling, budgeting, or data tables within PeachText.

PeachText 5000 runs under MS-DOS or CP/M on IBM PC compatibles and similar machines. When a user saves a worksheet from PeachCalc using its Save command, a spreadsheet file is written to disk containing the grid data, numeric values, text labels, formulas, layout options, and any protected cells or blocks. Worksheets can be saved wholly, or in "values only" mode, which records computation results but omits underlying formula definitions. Saved files can later be loaded back into PeachCalc, which reconstructs all editable features.

Worksheet size supports up to 254 rows by 64 columns. Cells may hold text (labels) or numeric data, and formulas support arithmetic, relational operations, statistical and financial functions, including square roots and trigonometry. The interface supports splitting the display into windows, locking rows or columns, and moving or formatting cell ranges.

Internal identification includes a clear byte signature: files begin with the ASCII string "PeachCalc ver" at offset zero. This signature differentiates these files from other spreadsheet or calendar-type formats that use the same extension.

QV Map Calibration Data File

A QV Map Calibration Data File holds the georeferencing information used by Touratech's QV (QuoVadis/QV GPS) software to align a map image with real-world coordinates. It is produced by Touratech QV's map calibration process, which attaches precise latitude/longitude or projected coordinate points, projection parameters, datum and scale so that the map image can be shown in correct position on the earth. It is useful whenever a raster map (e.g. scanned or bitmap image) lacks built-in georeferencing data.

The file is written by TTQV4 (Touratech QV version 4) and earlier versions during map‐export or calibration save. Newer versions such as QV6 no longer write this file as the primary calibration format; they use a replacement format (calx) for internal calibration and style storage. Only when exporting for compatibility with older QV versions is this format still generated.

Internally, the file is plain text (ASCII) and begins with a signature line ";Calibration" at the very start. It contains keyword/value pairs including SCALE_AREA, PROJPARAMS, PROJ_MODE, geographical corner coordinates (C1_LAT, C1_LON, C2_LAT, C2_LON), a datum identifier, file name (FNAME), and pixel-based corner positions (C1_X, C1_Y etc.). These tags allow the software to map image pixels to geographic reference.

SuperCalc Spreadsheet File

SuperCalc Spreadsheet files store full worksheets created in the SuperCalc family of spreadsheet programs (versions 4 and 5), developed originally by Sorcim and later by Computer Associates. These files contain all the data in a worksheet - including text, numbers, formulas, formatting, cell protection, global options, and any menus or window split settings used within the SuperCalc environment.

After a worksheet is created and edited interactively in SuperCalc - entering data in cells, setting row/column widths, formats (such as integer, fixed-point, scientific, text alignment), protecting or hiding cells - the "Save" operation writes everything to one of these files. When a saved file is later opened in SuperCalc or SuperCalc-5, the program reconstructs the worksheet exactly as when it was saved: cell values appear, any formulas behave, layout and format are retained. Only SuperCalc-4 and SuperCalc-5 recognize files in this original binary format without conversion. Worksheets saved in this way preserve circular-reference support, title rows/columns ("freeze titles"), and user-specified display formatting.

The format is binary and identifiable by a signature at the start of the file. It begins with the ASCII string "SuperCalc ver " followed by a version number (for example "5.") occupying the first bytes.

Windows Calendar File

Windows Calendar File data store calendar entries including appointments, notes, daily "marks" (box, circle, etc.), and alarm settings used by Microsoft Windows Calendar (the Calendar.exe program used in Windows 3.x). It records both per-day metadata (such as whether the day is marked, how many alarms are set, and the date) and per-appointment data including time, description, and flags.

This format is produced by Calendar.exe under Windows 3.1. The program also lets the user set global options (alarm behavior, sound, interval between appointments, 24-hour format, start time) which are stored in the file header. When Windows Calendar reads this file it uses that global header, then a sequence of "date descriptor" records to locate each day's data, followed by day‐specific structures covering notes and individual appointment items.

The format begins with an 8-byte magic value spelling "CALENDAR" in a special encoded form (bytes B5 A2 B0 B3 B3 B0 A2 B5 at file start). Following that is a 2-byte count of days described, then global header fields, followed by the date descriptor array (each descriptor is 12 bytes: date, mark flags, number of alarms, file block offset to that day's detail, reserved fields), then detailed per-day and per-appointment records.

Various apps that use files with this extension

These apps are known to open certain types of CAL files. Remember, different programs may use CAL files for different purposes, so you may need to try out a few of them to be able to open your specific file.

Help us help others

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