About This Pregnancy Week Calculator

Tracking your pregnancy week helps you understand fetal development, plan tests, and anticipate symptoms. This Pregnancy Week Calculator converts LMP or due date into the current gestational age and trimester. Each week brings new milestones—from heartbeat detection to fetal movement. Use our week-by-week calendar to see detailed development notes, checklists, and suggested prenatal tests.

Weekly highlight: Pregnancy is divided into three trimesters:

First trimester: Weeks 1-12
Second trimester: Weeks 13-26
Third trimester: Weeks 27-40

Each stage has unique developments and considerations for both mother and baby.

Baby Gender Prediction

Many parents are curious about their baby's gender during pregnancy. While the most accurate methods are medical (ultrasound and NIPT), there are several traditional methods people enjoy for fun:

Ultrasound: 95-99% accurate at 18-20 weeks
NIPT: 99% accurate from 9 weeks
Nub Theory: 75% accurate at 12-14 weeks

Chinese Gender Chart: Traditional method
Shettles Method: Based on timing of conception
Heart Rate Method: Based on fetal heart rate

For detailed information about these methods, including accuracy rates and how they work, visit Baby Gender Prediction Methods.

Frequently Asked Questions

What counts as week 1?

Pregnancy weeks are counted from the first day of your last menstrual period (LMP), not from conception. This means that week 1 and week 2 are technically before conception occurs. This method is used because the exact date of conception is often unknown.

When is the first trimester?

The first trimester includes weeks 1 through 12 of pregnancy. This is a critical period for fetal development when major organs and systems are forming. It's also when many women experience early pregnancy symptoms like nausea and fatigue.

How is gestational age different from fetal age?

Gestational age is measured from the first day of the last menstrual period and is typically about 2 weeks longer than fetal age, which is measured from conception. Healthcare providers usually refer to gestational age when discussing pregnancy milestones.

Can I track symptoms by week?

Yes, many pregnancy symptoms are associated with specific weeks or trimesters. For example, morning sickness often occurs during the first trimester, while fetal movement is typically felt during the second trimester. However, every pregnancy is unique, and experiences can vary.

How accurate is week calculation?

Week calculation based on LMP is generally accurate for women with regular 28-day cycles. For those with irregular cycles or uncertain LMP, ultrasound measurements can provide more accurate dating. Your healthcare provider may adjust your due date based on ultrasound findings.

Pregnancy Week Calculator — See What Week You're In