When is ovulation day? How do you know the ovulation day?

It can be calculated according to the menstrual period.

The so-called first seven and then eight, that is, the seventh day before menstruation, is a dangerous period, that is, ovulation period.

The last eight days are the eighth day after menstruation, which is a critical period, that is, ovulation period. If the menstrual period is on the first day of each month, the difficult ovulation period is 16~23, during which pregnancy is easy.