Question 1

How is a due date calculated?

Accepted Answer

The most common method is Naegele's Rule: add 280 days (40 weeks) to the first day of your last menstrual period. Our calculator also adjusts for cycle length and supports conception date entry.

Question 2

How accurate are due date calculators?

Accepted Answer

Due dates are estimates. Only about 5% of babies are born on their exact due date. Most are born within two weeks before or after the estimated date.

Question 3

What if my cycle is longer or shorter than 28 days?

Accepted Answer

Our calculator lets you enter your average cycle length (21-45 days) for a more personalized estimate, adjusting the due date accordingly.