Ovulation is the time when an egg is released from a woman's body, usually about 14 days before the next menstrual period. After the egg is released, it usually only survives for about 1-2 days. Therefore, it is easier to get pregnant if you have sexual intercourse during the ovulation period.

In addition to calculating ovulation, there are other ways to help determine when you're more likely to get pregnant by having intercourse. For example, body temperature measurement or B-ultrasound monitoring can be used to determine ovulation. These methods can help more accurately predict when having intercourse is more likely to lead to pregnancy.

Calculating ovulation and determining how long your eggs will survive is important in planning a pregnancy. If you're not sure how to calculate it, it's best to consult your doctor or a professional fertility consultant for accurate calculations and advice.