Date Calculator performs a variety of calendar related functions, useful in business. It will display a Perpetual Calendar (a calendar for any month of any year). It will calculate the number of days Between two dates, optionally not counting certain days of the week, such as Saturday and Sunday. It can also be programmed to skip holidays. It can also calculate the date N days before or after a given date, again optionally only counting certain user selected days of the week. It can automatically remind you of your appointments for the day, or show you a list of all your stored appointments, or only those appointments on any date you select. It has a feature for creating user defined sequences that will aid in the calculation of LUCAS, Gann, and Fibonacci turn dates. It has a separate mode that allows you to calculate time in terms of calendar years, months and days, as well as the standard mode of calculating exact days. It can display a perpetual calendar of any month of any year.