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Pregnancy dates & due-date calculator
Explore estimated due date, gestational weeks and a conventional conception reference.
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How this calculation works
LMP+280 days is a conventional estimated due date for a 28-day cycle. The conception reference is EDD−266 days, assuming day 14 ovulation; it is not the actual conception date or a fertility window. Clinical ultrasound/history can change dating. Use the clinician-established EDD when available; do not use for paternity, contraception or deciding care timing.
Reference: method and limitations. Method reviewed October 22, 2026.
Check the assumptions
Health calculations are educational estimates and do not replace a clinician’s assessment. Your inputs and individual circumstances can materially change how useful an estimate is.