Pregnancy Conception Calculator

Estimate conception date from due date or last menstrual period.

Pregnancy Conception Calculator helps you estimate conception date from due date or last menstrual period. Enter date, review the breakdown, and use the guidance below to understand what the number means — and what it does not. What the Pregnancy Conception calculator does Pregnancy Conception Calculator is built for body measurements, calories, and everyday health math. Estimate conception date from due date or last menstrual period. You enter date, then Simple Calculators computes the result instantly. These tools use widely published formulas. They are educational screens, not a diagnosis. How the math works Choose your Known date — Last menstrual period or Due date — then enter the date. From a last period, conception is estimated at 14 days later and the due date at 280 days (40 weeks) later. From a due date, it counts back 266 days (38 weeks) for conception and 280 days for the last period. It also shows how far along the pregnancy is today, the fertile window and trimester dates, and assumes a regular 28-day cycle. The formula: Conception ≈ first day of last period + 14 days; Conception ≈ due date − 266 days. Assumes a 28-day cycle and a 280-day pregnancy counted from the la…