Free tool
Due Date Calculator
Enter the first day of your last period to estimate your due date, how far along you are, and which trimester you're in. Everything is calculated in your browser.
This is an estimate based on Naegele's rule (last period + 280 days). Only about 1 in 20 babies arrive on the exact due date. Your doctor's dating scan is more accurate — always follow your obstetrician's guidance. This tool is not medical advice.