Pregnancy Due Date Calculator
Estimate your due date based on your last menstrual period.
About this Tool
The Pregnancy Due Date Calculator estimates your baby's due date based on the first day of your last menstrual period (LMP). This method, known as Naegele's rule, is a standard way healthcare providers estimate a due date. It assumes a 28-day menstrual cycle, with ovulation occurring on day 14. The calculator adds 280 days (40 weeks) to the LMP to predict the due date.
Common Use Cases
Due Date Estimation
Get a quick estimate of your baby's due date to help you plan for the arrival.
Tracking Pregnancy
Understand how far along you are in your pregnancy in weeks.
Doctor's Visits
Use this estimate as a starting point for discussions with your healthcare provider, who will provide a more accurate date based on ultrasound.
Pro Tips
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This is an Estimate
Only about 5% of babies are born on their exact due date. It's more of a guideline for when you can expect your baby.
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Cycle Length Matters
This calculator assumes a 28-day cycle. If your cycle is longer or shorter, your actual due date may differ. Your doctor can provide a more accurate date.
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Ultrasound is More Accurate
An early ultrasound, usually in the first trimester, is the most accurate way to determine a baby's gestational age and due date.