Naegele's Rule Calculator

Calculate Expected Date of Delivery (EDD)

Formula

The formula to calculate the Expected Date of Delivery (EDD) using Naegele's Rule is:

\[ EDD = LMP + 1 \, \text{year} - 3 \, \text{months} + 7 \, \text{days} \]

Where:

What is Naegele's Rule?

Naegele's Rule is a standard method used by obstetricians to estimate a pregnant woman's due date. The rule calculates the expected date of delivery by adding one year, subtracting three months, and adding seven days to the first day of a woman's last menstrual period. This method assumes a 28-day menstrual cycle with ovulation occurring on the 14th day, and a standard gestation period of 280 days from the last menstrual period to the birth of the baby.