Conception Date Calculator
Estimate when conception likely occurred based on your due date or last menstrual period.
How Conception Date is Estimated
Conception occurs when a sperm fertilizes an egg, typically during the ovulation window — about 12–16 days after the first day of your last menstrual period in a 28-day cycle.
From due date: Conception Date ≈ Due Date – 266 days (38 weeks)
From LMP: Conception Date ≈ LMP + 14 days (for a 28-day cycle)
Sperm can survive 3–5 days inside the female reproductive tract, so conception can occur a few days before or after the detected ovulation date.
FAQs
Is the conception date exact?
No. It's an estimate based on averages. Actual conception may differ by several days depending on cycle length and ovulation timing.
Can I determine the father from conception date?
Conception date estimates have a ±5 day range. For paternity determination, a DNA test is the only accurate method.