The fertile window - time for inter course

 The fertile window is the time during a menstrual cycle when a person is most likely to get pregnant. It usually includes: the five days before ovulation, the day of ovulation, and the day after ovulation.

In most women, ovulation occurs around 10 to 16 days before the next period. However, the timing can be unpredictable, even for people with regular cycles. 

You can use an ovulation predictor kit to help you time intercourse. You test your urine a few days before you expect to ovulate, and you should ovulate 24–36 hours after the test turns positive

Sperm can live in a woman's body for up to five days, while an egg can survive for about 12 to 24 hours after ovulation

https://www.yourfertility.org.au/everyone/timing