Pregnancy Due Date Calculator
Calculate your estimated due date (EDD) from your last menstrual period (LMP), conception date, or IVF transfer date. Includes trimester breakdown and key milestones.
Cycle length:
days
Frequently asked
questions
Using the last menstrual period (LMP), the due date is calculated by adding 280 days (40 weeks) — a method known as Naegele's rule. This assumes a 28-day cycle and ovulation on day 14. IVF dates are calculated differently based on transfer day.
Pregnancy is divided into three trimesters. The first trimester is weeks 1–12, the second is weeks 13–26, and the third is weeks 27–40. Each trimester involves different developmental milestones.
Only about 5% of babies are born on their exact due date. Most births occur within 2 weeks before or after the EDD. An ultrasound measurement, especially in the first trimester, provides a more accurate estimate.