You can use the following methods to check ovulation: 1. You can monitor your basal body temperature to know which day you ovulate, when the basal body temperature appears bi-directional, the day before the basal body temperature appears bi-directional is basically the day of ovulation, 4 days before and 3 days after ovulation is the ovulation period. 2. The growth and development of the follicle will reach 20mm in diameter on the 16th day of menstruation and the follicle will rupture and expel the egg. 3, you can also take a blood test for luteinizing hormone to find out the ovulation period.