Pregnancy Due Date Calculator - Estimate Your Due Date Free Due Date Calculator
Enter the first day of your last menstrual period and your average cycle length to estimate your due date, conception date, trimester milestones and current gestational age.
Period Details
Pregnancy Estimate
Key Milestones
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Pregnancy Due Date Calculator - Guide
What is a Due Date Calculator?
A Pregnancy Due Date Calculator estimates when your baby is likely to be born. It uses the first day of your last menstrual period (LMP) and your average cycle length to calculate the estimated due date (EDD) using Naegele’s Rule.
Naegele’s Rule
EDD = LMP + 280 days + (Cycle Length − 28)
For a standard 28-day cycle, the due date is simply the LMP + 280 days (40 weeks).
Example:
- LMP = January 1, 2025
- Cycle Length = 28 days
- EDD = January 1 + 280 days = October 8, 2025
Trimester Breakdown
- 1st Trimester (Weeks 1–12): Major organs begin to form. Morning sickness and fatigue are common.
- 2nd Trimester (Weeks 13–27): Baby grows rapidly. Many consider this the most comfortable trimester.
- 3rd Trimester (Weeks 28–40): Baby gains weight and prepares for birth. Braxton Hicks contractions may begin.
Accuracy & Disclaimer
Only about 5% of babies are born on their exact due date. Most births occur within 2 weeks before or after the EDD. This calculator provides an estimate only and is not a substitute for professional medical advice. Please consult your healthcare provider for personalised guidance.
How This Calculator Works
- LMP Date: Select the first day of your last menstrual period using the date picker.
- Cycle Length: Enter your average menstrual cycle length (default is 28 days).
- Results: View your estimated due date, conception date, trimester milestones, gestational age and pregnancy progress.