🗓️ CONCEPTION & FERTILITY TIMING
Pregnancy Conception Calculator
Estimate your probable conception date and fertile window based on your due date or last menstrual period.
Enter Your Known Date
Feb 22, 2026
Most probable date of ovulation and fertilization.
Feb 17 – Feb 23, 2026
Nov 15, 2026
Understanding Conception Timing
Conception typically occurs when an egg is fertilized by a sperm, usually within 24 hours of ovulation.
- Fertile Window: Sperm can survive inside the female reproductive tract for up to 5 days, making conception possible from intercourse up to 5 days prior to ovulation.
- Gestational vs Embryonic Age: Gestational age starts from the first day of the last period (LMP), while embryonic age starts from the actual conception date (approx. 2 weeks later).
Biological Variation Note:
Conception dates are clinical estimations. Sperm viability and individual ovulation variance mean the exact day of fertilization can fluctuate by several days.
Frequently Asked Questions
How far back from my due date is conception?
Conception occurs approximately 266 days (38 weeks) before your estimated due date.