Enter the first day of your last period and your typical cycle length to estimate your fertile window.
Ovulation usually happens about 14 days before your next period. Because sperm can survive several days, the "fertile window" spans roughly the 5 days before ovulation through the day after. These dates are estimates , tracking symptoms or using ovulation tests improves accuracy.
The most fertile days are the 2-3 days leading up to and including ovulation, which is roughly 14 days before your next period.
It's a good estimate for regular cycles but assumes a 14-day luteal phase. Ovulation tests or symptom tracking are more precise.