Health
Pregnancy due date calculator
An estimated due date gives a pregnancy its shape: appointments, planning, and the finish line. Enter the first day of your last menstrual period — or a known conception date — and your average cycle length. The calculator applies the standard obstetric rules (280 days from the last period, adjusted for cycle length, or 266 days from conception), estimates the conception window, and shows how many weeks along the pregnancy is as of today. Every estimate is a midpoint, not a deadline; most babies arrive within about two weeks of the date.
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Pregnancy Due Date Calculator
Estimate a due date from your last period or conception date.
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How it works
- 01
From the first day of your last period, the estimate adds 280 days, adjusted by your average cycle length (Naegele's rule).
- 02
From a known or estimated conception date, it adds 266 days.
- 03
Progress counts completed weeks and days from the start date to the date shown, using standard obstetric counting.
Try a real scenario
Last period June 1
InputsLMP June 1, 28-day cycle
ResultEstimated due date around March 8, with conception near June 15.
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