How to Calculate Your Due Date?
The estimated due date (EDD) is calculated by adding 280 days (40 weeks) to the first day of your last menstrual period. This is Naegele's rule, used by most healthcare professionals.
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Different Calculation Methods
1. Naegele's Rule: Most common, based on a 28-day cycle.
2. First Trimester Ultrasound: More accurate, measures crown-rump length.
3. Conception Date: If known, add 266 days.
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Factors Affecting the Date
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Calculation Accuracy
Only 4% of babies are born exactly on their due date. Most are born between 38 and 42 weeks.
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Our Calculator
Use our due date calculator for your personalized estimate.