Pregnancy Week Calculator
Calculate how many weeks pregnant you are, your trimester, and your estimated due date.
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Frequently Asked Questions
When is my due date?
The standard due date is 280 days (40 weeks) from the first day of your last period, assuming a 28-day cycle. For longer or shorter cycles, the due date adjusts accordingly. Only about 4% of babies are born on their exact due date — most arrive within 2 weeks before or after.
What are the three trimesters?
First trimester: weeks 1-12. Second trimester: weeks 13-26. Third trimester: weeks 27-40. The second trimester is often considered the most comfortable — morning sickness has typically passed and the belly isn’t yet very large.