To calculate your menstrual cycle, count the days between your last few periods. Begin counting on the first day of your period to the day before your next period. Do this for a few cycles, and add up the total number of days, dividing it by the number of cycles. This will give you the average length of your menstrual cycle.
If you want to calculate your menstrual cycle length average, add all three cycle lengths together (29+30+29=88). Next, divide by the total number of months we used (3), and you get an average menstrual cycle length of 29.33 days (rounded to 29 days).
Note that the day you count as the actual day your period starts is the day you had an actual flow of menstrual blood, NOT just spotting.
I hope this helps!
