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ARVENRA
Pregnancy & reproductive health

Due Date Calculator

Your estimated due date and pregnancy milestones, using Naegele's rule.

The estimated due date is 280 days after the first day of your last period. If your cycle differs from 28 days, the tool corrects for it.

Your details

From the first day of one period to the first day of the next. Default 28 days.

Typical range: 20 – 45

The values you enter are calculated in your browser only — nothing is stored or transmitted.

Fill in your details and press calculate — your result will appear here.

Formula and method

Naegele's rule with a cycle-length correction, plus the trimester boundaries and the start of full term.

Formula used

Naegele's rule: LMP + 280 days, adjusted for cycle length

Assumptions and limits

  • Only about five percent of babies arrive exactly on the estimated date; it is the centre of a range.

Scientific sources

  1. American College of Obstetricians and Gynecologists. “Committee Opinion No. 700: Methods for Estimating the Due Date.” Obstet Gynecol. 2017;129(5):e150-e154.

    View source

  2. American College of Obstetricians and Gynecologists. “Committee Opinion No. 700: Methods for Estimating the Due Date.” Obstet Gynecol. 2017;129(5):e150-e154.

    View source

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