Pregnancy Calculator
Due date (Naegele's rule) plus current week and trimester.
Result
Pregnancy Calculator — FAQs
How is a due date calculated?
Naegele's rule: LMP + 280 days (40 weeks), adjusted for cycle length — a 35-day cycle pushes the date ~7 days later.
How accurate is it?
Only ~4–5% of babies arrive on the due date; 90% arrive within 2 weeks either side. The 12-week scan gives a more accurate dating.
How is due date calculated?
Naegele's rule: last menstrual period + 280 days (40 weeks). Only ~4% of babies arrive on the exact date — 37–42 weeks is normal term.
How many weeks pregnant am I?
Counted from the first day of your last period, not conception — conception is typically ~2 weeks later.
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