Generally, ovulation occurs about one week after menstruation. Under normal condition, the menstrual cycle is about 28 days, if you have 7 days of menstrual bleeding, according to the 28-day menstrual cycle, the ovulation day is about the 14th day of menstruation, so ovulation will occur 7 days after 7 days of bleeding and 7 days after clean, which is calculated according to the general menstruation. If the usual menstrual cycle is accurate, basically ovulation will occur 7 days after menstruation. If the usual menstruation is very inaccurate, to calculate the ovulation day, you can count down 14 days from the date of the next menstruation, which is relatively accurate.