Health & Fitness
Due Date Calculator
Calculate your pregnancy due date based on your last menstrual period.
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Used to calculate your estimated due date
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What is Due Date Calculator?
A due date calculator estimates the expected date of delivery based on the first day of the last menstrual period (LMP) or a known conception date. While the actual delivery date varies, this calculation gives parents and healthcare providers a 40-week target for planning and prenatal care.
How to Use
- Enter the first day of your last menstrual period
- Or enter the conception date if known
- View the estimated due date and current week of pregnancy
- See trimester milestones and key development stages
Formula
Due Date = LMP + 280 days (Naegele's Rule), or Conception Date + 266 days
Frequently Asked Questions
- How accurate is the estimated due date?
- Only about 5% of babies are born on their exact due date. Most healthy deliveries occur between 37 and 42 weeks. The due date is a midpoint estimate.
- What if my cycle is longer or shorter than 28 days?
- Adjust by adding or subtracting days. If your cycle is 35 days, add 7 days to the standard due date. Your doctor may adjust based on early ultrasound measurements.
- When do trimesters start and end?
- First trimester: weeks 1-12. Second trimester: weeks 13-26. Third trimester: weeks 27-40. Each trimester brings different developmental milestones and symptoms.