Perpetual Calendar - Version 2.3 A Windows calendar that allows you to display and print any month or year. It also has utilities for determining the Julian date and allows you to add and subtract periods to or from a date. For example, you could enter a date and subtract 232 days to determine the result. Likewise you could add 34 months to determine the result. You can add/subtract days, weeks, months, quarters and years. Free to try and only $15.00 to buy.