TeeNee Calculator
Pregnancy tools for expecting parents

Pregnancy Due Date Calculator

Enter the first day of your last period to estimate your due date, current pregnancy week, trimester, and approximate baby size.

Calculate your due date

Enter your cycle details

The calculation uses 40 weeks and adjusts for your average cycle length.

Use 28 days if you are unsure.
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See both the date and your current stage

This page goes beyond a single date. It summarizes the current week, trimester, approximate size, and key pregnancy dates in easy-to-read cards.

The 280-day estimate

A standard estimated due date is 280 days from the first day of the last menstrual period.

Cycle lengths from 21-45 days

The due date and related pregnancy dates adjust in the same direction as your average cycle length.

Clear English dates

Dates are displayed with English month names so they are easy to read and share.

Pregnancy tools in this series

Move easily from cycle tracking to ovulation, gestational age, due date, conception date, and a week-by-week chart.

Important note

All results are estimates intended to provide a helpful overview. They do not replace an ultrasound, diagnosis, or medical advice. Length is shown around a weekly reference value. Weight ranges from week 22 use the 10th-90th percentiles from the INTERGROWTH-21st standard.

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