Pregnancy Due Date
Estimating Your Due Date
Knowing your estimated due date (EDD) is an exciting part of pregnancy. It helps you prepare for your baby's arrival and allows your healthcare provider to monitor your baby's growth accurately. Pregnancy normally lasts about 280 days (40 weeks) from the first day of your last menstrual period (LMP).
How is it Calculated? (Naegele's Rule)
This calculator uses Naegele's Rule, the standard method used by doctors worldwide. It assumes a regular 28-day cycle.
1. Determine the first day of your Last Menstrual Period (LMP).
2. Add 7 days.
3. Subtract 3 months.
4. Add 1 year.
Example: If your LMP was November 1, 2023:
+7 days = November 8
-3 months = August 8
+1 year = August 8, 2024 (Estimated Due Date)
Trimesters Guide
- First Trimester: Week 1 to Week 12
- Second Trimester: Week 13 to Week 26
- Third Trimester: Week 27 to Week 40+
FAQ
Is the due date exact?
No, it is an estimate. Only about 4% of babies are born on their exact due date. Most babies are born within a week before or after the estimated date.
What if I don't know my LMP?
If you have irregular periods or don't maintain a cycle calendar, an early ultrasound is usually the most accurate way to date the pregnancy.