Pregnancy Due Date Calculator
Calculate your estimated pregnancy due date using Naegele's rule. See current week of pregnancy, trimester, and days remaining.
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Naegele's Rule
Due Date = LMP + 280 days
This estimates the due date based on a standard 40-week pregnancy from the first day of the last menstrual period.
Frequently Asked Questions
What is Naegele's rule?
Naegele's rule estimates the due date by adding 280 days (40 weeks) to the first day of the last menstrual period (LMP). It assumes a 28-day menstrual cycle with ovulation on day 14.
How accurate is the due date?
Only about 5% of babies are born on their exact due date. Most deliveries occur within 2 weeks before or after the estimated date. It serves as a guideline rather than an exact prediction.
What are the three trimesters?
First trimester: weeks 1-12 (organ formation). Second trimester: weeks 13-26 (growth and movement). Third trimester: weeks 27-40 (final development and preparation for birth).