How to calculate the date in heavenly stems and earthly branches Chronology? As long as the day is counted in the answer, it is clear.

Ri heavenly stems and earthly branches

The formula for calculating the branch date according to the known date is:

g = 4C+【C/4】+【5y】+【y/4】+【3 *（m+ 1）/5】+d-3

z = 8C+【C/4】+【5y】+【y/4】+【3 *（m+ 1）/5】+d+7+I

Where c is the number of centuries minus 1. Odd months i=0, even months i=6, the first two digits of the year, Y is the last two digits of the year, M is the month, and D is the number of days. [] represents an integer.

65438+ 10 and February are calculated according to 65438+March and 65438+April of the previous year, so c and y should also be calculated according to the year of the previous year.

The remainder of g divided by 10 is heavenly stems, and the remainder of z divided by 12 is earthly branches.

If g is obtained first, then

Z=g+4C+ 10+i (i=0 for odd months and i=6 for even months)

For example:

July 65438 +6, 2009

G = 80+5+45+2+4+16-3 =149, the remainder is 9, and the heavenly stems are "nonyl".

Z =149+80+10+0 = 239, the remainder is 1 1, and the ground branch is "zero".