Tool
Due Date Calculator
Enter the first day of your last menstrual period and your average cycle length. We will calculate your estimated due date using Naegele's rule, the same method used by Australian midwives and obstetricians.
This is the date your last period started, not when it ended.
Most people have a 28-day cycle. Adjust if yours is different.
This calculator uses Naegele's rule: last menstrual period plus 280 days, adjusted for cycle length. It is designed as a guide only. Your healthcare provider will confirm your due date by ultrasound, typically at your dating scan between 8 and 12 weeks.