Pregnancy Due Date Calculator

Calculate your estimated due date, current gestational age, and track pregnancy milestones.

Calculation Method

First Day of Last Menstrual Period (LMP)

Average Cycle Length (days)

Trimester Overview

First Trimester

Weeks 1-12

Major organ development. Morning sickness common. Highest risk of miscarriage.

Second Trimester

Weeks 13-26

Baby grows rapidly. Mother feels movement. Generally most comfortable trimester.

Third Trimester

Weeks 27-40

Final growth phase. Baby gains weight. Preparation for delivery.

Important Note

This calculator provides an estimate only. Only about 5% of babies are born on their exact due date. Most babies arrive within two weeks before or after the estimated due date. Always consult with your healthcare provider for personalized guidance.

About Due Date Calculations

Naegele's Rule

The most common method for calculating due dates is Naegele's Rule, which adds 280 days (40 weeks) to the first day of the last menstrual period (LMP). This assumes a 28-day cycle with ovulation occurring on day 14.

Ultrasound Dating

First-trimester ultrasounds (before 14 weeks) are the most accurate for dating pregnancies. Crown-rump length measurements can predict due dates within 5-7 days. Later ultrasounds are less accurate for dating purposes.

IVF Pregnancies

For IVF pregnancies, the due date is calculated from the embryo transfer date. Day 5 embryos (blastocysts) are transferred 19 days after the "LMP equivalent," while day 3 embryos are transferred 17 days after.

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