Finding the date of Easter, the beginning of Lent, the significant days of Holy Week, Ascension Day, and Pentecost could not be easier than with the Computus app. This simple app allows you to enter any year after 1583 (the first Easter after the beginning of the Gregorian calendar) and find the dates of the holy days associated with Easter for both Western and Orthodox Christians.
Orthodox observances are calculated on the Julian calendar and converted to the standard Gregorian date across the entire range of available years.
The name Computus comes from the Latin term meaning calculation and has been used since medieval times for the process of calculating the date of Easter.