Ovulation usually occurs 8-10 days in a month, with some individual differences. Normally, if a woman has a regular period, the 14th day before her next menstrual period is the day of ovulation, and the 4-5 days before and after the day of ovulation are the days of ovulation. Ovulation usually occurs 14 days before or 14 days after the first day of the woman’s next menstrual period. Generally, the first 5 days and the last 4 days of the ovulation day are added together and called the ovulation period. If your period is irregular, the ovulation date calculated will not be accurate. It is also important to note that menstruation should be susceptible to changes in the cycle due to the usual rhythm of life, emotions, diet and lifestyle, etc. Even if a woman usually has regular periods, her calculated ovulation date may not be accurate. In general, the egg survival time is about 24 hours. If you are not planning to conceive, you should pay attention to good contraceptive measures.