The ideal time to have intercourse to conceive is about 12-24 hours before ovulation. Ovia will predict the most fertile day of your fertile window with a Fertility Score of 10. Generally, your ovulation date occurs about two weeks before the first day of your period. However, intercourse a few days before, during, or just after ovulation can still lead to conception, because sperm can live for several days and eggs survive up to 12-24 hours after ovulation. Read more here and here.