Free conception date calculator to estimate when you conceived based on due date, last menstrual period, or ultrasound measurements.
You might also find these calculators useful
Wondering when you conceived? This calculator estimates your conception date and fertile window based on your due date or last menstrual period. Understand when pregnancy likely began.
Conception occurs when sperm fertilizes an egg, typically within 24 hours of ovulation. Ovulation usually happens about 14 days after the first day of your last menstrual period (in a 28-day cycle). Sperm can survive up to 5 days in the reproductive tract, so the fertile window extends from 5 days before to 1 day after ovulation.
Conception Date Estimate
Conception ≈ LMP + 14 days (adjusted for cycle length)Verify or estimate pregnancy dating when LMP is uncertain.
Understand your fertile window for future pregnancy planning.
Provide estimated conception information to healthcare providers.
No—conception is estimated within a range. Sperm can fertilize an egg for up to 5 days after intercourse, and the exact moment of fertilization can't be determined without IVF tracking.