Due Date & Pregnancy Calculator
Calculate your due date and track your pregnancy progress
Pregnancy Details
Pregnancy Summary
Pregnancy Timeline
First Trimester
Weeks 1-13
Early development, major organs begin to form.
Second Trimester
Weeks 14-27
Baby grows rapidly, you may feel movement.
Third Trimester
Weeks 28-40
Final growth phase, baby prepares for birth.
Weekly Development
| Week | Size | Development |
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About Due Date Calculation
Due date calculation is typically based on Naegele's rule, which estimates the expected date of delivery (EDD) by adding 280 days (40 weeks) to the first day of the last menstrual period (LMP).
The formula for Naegele's rule is:
EDD = LMP + 280 days
This calculation assumes a 28-day menstrual cycle with ovulation occurring on day 14. For women with longer or shorter cycles, the due date can be adjusted:
Adjusted EDD = LMP + 280 days + (cycle length - 28 days)
If the conception date is known, the due date can be calculated by adding 266 days (38 weeks) to the conception date, as pregnancy is typically 38 weeks from conception.
It's important to remember that only about 5% of babies are born on their exact due date. Most births occur within two weeks before or after the estimated due date.
This calculator provides an estimate based on standard obstetric calculations. Always consult with your healthcare provider for personalized medical advice.