Date Calculator performs a variety of calendar related functions, including a perpetual calendar, calculating the number of days between two dates, the date of the day a certain number of days from a certain date, and the day of the week for a given date. You can set it to count only certain days of the week, such as Monday through Friday, and whether to count the first and last day of the date range provided. It will automatically calculate costs if you are paying a certain amount per day. Version 5.2 now 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.