DateCalc is a simple date calculator. It has following functions:
- Adding amount of days to a date.
- Substracting amount of days from a date.
- Calculating days difference between two dates.
- Determining a weekday for a date.

Features of the program are:
- Eight preset buttons (one for today date, seven user configurable).
- Wide range of dates, from 1 Jan 1 (using proleptic Gregorian calendar) to 31 Dec 9999.
- Copying result to system clipboard.


Entering a date

A date is always the first and for "- Date" also the second argument. Dates are entered to DateCalc in YYYY-MM-DD format. Entering can be done by either clicking on gadgets or using keyboard. Numeric pad keys work too. Note that dashes are entered automatically. Date can be also entered by clicking on a programable preset button.


Adding an amount of days to a date

Enter date, it will be shown in the first argument field. Then press "+ Days" button. Enter number of days. Press "=".


Substracting an amount of days from a date

The same as above, but use "- Days" operator button.


Day difference between two dates

Enter the first date as described above, press "- Date", enter the second date (you can use a preset button too), press "=".


Determining a weekday of a date

Enter the date. Then press either "+ Days" or "- Days" (does not matter which one) and then "=". Read the weekday from the result.


Keyboard shortcuts

Menu shortcuts are displayed on the right of respective menu items. Shortcuts for buttons are:
- "+" for "+ Days" button. Numeric pad "+" works too.
- "-" for "- Days" button. Numeric pad "-" works too.
- "/" for "- Date" button. Numeric pad "/" works too.
- "c" or spacebar for "C" (clear) button.
- Enter or numpad return or "=" for "=" button.
- F1 and numeric pad "*" for "Today" button.
- F2 to F8 for preset buttons.


Programming preset buttons

Use "Preset Buttons" menu item to open a programming window. Enter labels and dates. Labels are limited to 12 characters. Dates must be entered in YYYY-MM-DD format. If date is wrong, corresponding button will be disabled. "Save" button saves defined presets to disk.


Copying result to the clipboard

Use "Copy" menuitem or standard RCOMMAND+C keyboard shortcut.


What is the proleptic Gregorian calendar?

Proleptic Gregorian calendar is the result of assumption that Gregorian calendar rules were used from infinite time in the past. While this assumption is not true, it gives a simple and precise timescale. Different countries adopted Gregorian calendar in different points in time from 1582 to 1926. Proleptic calendar gives an uniform time scale for historicans and astronomers.


Author and license

Grzegorz Kraszewski <krashan@teleinfo.pb.edu.pl>
http://krashan.ppa.pl
http://twitter.com/digibooster3

DateCalc is Freeware. Use it at your own risk.