🤰 Pregnancy Conception Calculator

Estimate your conception date and window of fertility based on your due date or last menstrual period.

Understanding Conception

Conception occurs when a sperm fertilizes an egg, typically within 24 hours after ovulation. However, because sperm can survive in the female reproductive tract for 3-5 days, the fertile window is actually several days long.

The Fertile Window

  • 5-4 days before ovulation: Sperm can survive and wait for the egg
  • 3-1 days before ovulation: Increasing fertility
  • Day of ovulation: Peak fertility
  • 1 day after ovulation: Egg viable for 12-24 hours

Timeline of Early Pregnancy

Day Event
0 Conception (fertilization)
3-4 Embryo reaches uterus
6-12 Implantation occurs
14 hCG hormone detectable in blood
21 Home pregnancy test positive
266 Due date (38 weeks from conception)
Note: This calculator provides an estimate. The exact conception date can vary based on individual cycle length and ovulation timing.