Pregnancy Week Calculator

Find out exactly how many weeks pregnant you are and discover your current trimester and baby's development stage.

How Many Weeks Pregnant Am I?

Enter the first day of your last menstrual period to calculate your current pregnancy week

First Day of Last Menstrual Period (LMP)

Select the first day of your last menstrual period to calculate how many weeks pregnant you are.

Key Features

Calculate exact pregnancy weeks and days

Automatic trimester identification

Visual progress bar showing pregnancy completion

Baby development information by week

Easy sharing of pregnancy milestone results

Pregnancy Trimesters

1st Trimester

0-12 weeks • Organ development • Morning sickness common

2nd Trimester

13-27 weeks • "Golden period" • Baby movement felt

3rd Trimester

28+ weeks • Rapid growth • Preparation for birth

Key Weekly Milestones

6-8 weeks: Heartbeat detectable via ultrasound

12 weeks: End of first trimester, reduced miscarriage risk

20 weeks: Halfway point, anatomy scan performed

24 weeks: Viability milestone reached

37 weeks: Full-term pregnancy begins

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Frequently Asked Questions

How many weeks pregnant am I?

To calculate how many weeks pregnant you are, count the days from the first day of your last menstrual period (LMP) to today, then divide by 7. Our calculator does this automatically for accurate results.

How do you calculate pregnancy weeks?

Pregnancy weeks are calculated from the first day of your last menstrual period (LMP), not from conception. Count the total days since LMP and divide by 7 to get weeks and remaining days.

How many weeks is each trimester?

First trimester: 0-12 weeks, Second trimester: 13-27 weeks, Third trimester: 28-40+ weeks. Each trimester represents different stages of pregnancy and baby development.

What trimester am I in?

Your trimester depends on your pregnancy week: 1st trimester (0-12 weeks), 2nd trimester (13-27 weeks), or 3rd trimester (28+ weeks). Our calculator shows your current trimester automatically.

How accurate is the pregnancy week calculator?

The pregnancy week calculator is very accurate when based on a known last menstrual period date. It uses the standard medical calculation method used by healthcare providers worldwide.

When does each trimester start and end?

1st trimester: Week 1-12, 2nd trimester: Week 13-27, 3rd trimester: Week 28-40+. These divisions help track different phases of pregnancy development and care.

Important Medical Disclaimer

This pregnancy week calculator provides estimates only and should not replace professional medical advice.Pregnancy dating can vary based on individual factors and cycle irregularities. Always consult your healthcare provider for accurate pregnancy dating, monitoring, and medical advice throughout your pregnancy journey.