Pregnancy Due Date
Estimated due date from last menstrual period
For informational purposes only — not medical advice. Consult your doctor.
How to use
- Enter the first day of your last menstrual period (LMP).
- See estimated due date (40 weeks from LMP), weeks pregnant and trimester.
The formula (in simple words)
Naegele's rule: due date = LMP + 280 days (40 weeks). Only about 5% of babies arrive on the exact due date.
Frequently asked questions
Early ultrasound dating is often more accurate if cycles are irregular. Always follow your doctor's advice.