Windows software to convert between Julian, Gregorian, Dee and Dee-Cecil calendar dates in various formats, and to add and subtract a number of days, weeks, months and years to or from a given date. Also displays a sequence of Gregorian and Dee (or Dee-Cecil) dates for up to consecutive 800 days, and dates and times of vernal equinoxes in the Gregorian and Dee(-Cecil) calendars for up to 800 consecutive years. Times of vernal equinoxes may be calculated on the basis either of mean solar time or apparent solar time.

• Equinoxes, Solstices and Cross-Quarter Days 3.55
  This software calculates accurate dates and times for equinoxes, solstices and the Celtic cross-quarter days (Imbolc, Beltane, Lughnassad and Samhain). The cross-quarter days are...

• RamCal 2.1
  RamCal is a perpetual calendar that gives the day of the week for any given date

• Easy Date Converter 7.6
  Does date arithmetic (adds a number of days to a date and calculates the number of days between two dates) and converts among Gregorian dates, Julian dates, Annus Novus dates, Julian day numbers and day-in-year dates of the form yyyyddd