excel formula to subtract 2 of 7 days a week

In this guide, the notation “C.E.” and “B.C.E.” will be used.For more information on this reform and its consequences for calculating the day of the week, refer to the “Julian calendar” section of the Wikipedia article entitled “Doomsday rule”. Note that the Gregorian calendar has been reformed in the past and that this algorithm only applies to the Gregorian calendar in its most recent state.

Non-leap years will be referred to throughout the guide as “normal years.” The Gregorian calendar repeats exactly every 400 years.

with the exception that years divisible by 400 are leap years.

with the exception that years divisible by 100 are not leap years….

For March through December, the Sunday Letter is E. For January and February, the Sunday Letter is F (one letter back from the year before), but the leap day, February 29, causes a disruption. (again, back one letter from the year before - G is considered to be one letter back from A)

Know which letter is the Sunday Letter (a self-explanatory term) for the year you care about. |Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec| Here is a chart of day letters for the whole year: When we reach December 31, we will be back at the letter A for the fifty-third time. Note: This process can be used in reverse to find either the month, day, or year if any one of them is missing but the Day-of-the-Week is known.'Ĭontinue through all 365 days of the year this way.

This formula could even be extended further to encompass and compute the entire Year value in one felled swoop, but that formula, at its simplest, would be too complicated to carry around in one’s head and then perform the calculation quickly and precisely, which are the goals of the process explained here. For example, the 3400s would be 5 X (34-32) = 10 (and 10, when reduced by the 7s in it, equals 3). This value for any century can instead be computed by multiplying 5 times the difference between the (2-digit) century and the highest multiple of 4 in it. The four-number cycle (0-5-3-1) of the Century Table repeats itself indefinitely, as shown in the table by the 0 for century 2000. Using the resulting number, look up the day of the week in the Weekday-Table. If the resulting number is greater than 6, subtract the highest multiple of 7 in it.

Excel formula to subtract 2 of 7 days a week