What are the three trimesters of pregnancy?

1st Trimester: weeks 1–13. 2nd Trimester: weeks 14–26. 3rd Trimester: weeks 27–40. Full term is considered 37–40 weeks.

How accurate is the due date calculator?

This calculator gives an estimate. Only 5% of babies are born exactly on their due date. An ultrasound at 8–12 weeks gives a more accurate due date.

What is a normal pregnancy length?

A normal pregnancy is 38–42 weeks. Babies born at 37 weeks or later are considered full term.

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🤰 Pregnancy Due Date Calculator

Calculate your baby's estimated due date (EDD) and week-by-week pregnancy milestones.

First Day of Last Menstrual Period (LMP)

Average Cycle Length (days)

💡 Based on Naegele's rule: LMP + 280 days (40 weeks). Always confirm with your doctor via ultrasound.

How Pregnancy Due Date is Calculated

The estimated due date (EDD) is calculated using Naegele's Rule: add 280 days (40 weeks) to the first day of your Last Menstrual Period (LMP). This assumes a 28-day menstrual cycle. Our calculator adjusts for your actual cycle length — if your cycle is longer (e.g. 35 days), your due date shifts forward by the difference.

Only about 5% of babies are born exactly on their due date. 80% are born within 2 weeks before or after. Babies born between 37–42 weeks are considered full term.

Pregnancy Trimester Breakdown

1st Trimester (Weeks 1–12): Embryo development, most miscarriage risk, morning sickness peak
2nd Trimester (Weeks 13–26): Energy returns, baby's movements felt, anatomy scan at week 20
3rd Trimester (Weeks 27–40): Rapid growth, Braxton Hicks contractions, birth preparation

Key Prenatal Milestones

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Week 8–12: First Trimester Scan

Dating ultrasound confirms due date more accurately than LMP calculation. Measures crown-rump length (CRL) of embryo. Also checks for chromosomal abnormalities (NT scan).

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Week 16–20: Quad Screen Test

Blood test screening for Down syndrome, trisomy 18, and neural tube defects. Results guide whether amniocentesis is recommended.

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Week 20: Anatomy Scan

Detailed ultrasound checks all baby's organs, spine, limbs, and placenta position. Most parents also learn the baby's gender at this scan if desired.

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Week 36+: Weekly Checkups

Weekly monitoring checks baby's position, amniotic fluid levels, and cervical dilation. Hospital bag should be packed by week 36 — premature labour can happen anytime.