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 during or just after ovulation can still lead to conception, because eggs survive up to 12-24 hours after ovulation. Read more here and here.