Baby Due Date Calculator in Weeks

How to Use This Calculator

Using our baby due date calculator is simple:

1. Select whether you want to calculate based on your last menstrual period (LMP) or ultrasound date.
2. Enter the relevant date (LMP or ultrasound date).
3. Click "Calculate" to see your estimated due date.
4. Review the results and understand the pregnancy timeline.

The calculator provides both the due date and the current pregnancy week, helping you track your progress throughout your pregnancy.

How the Due Date Calculation Works

The standard pregnancy duration is 40 weeks (280 days) from the first day of the last menstrual period (LMP). The due date is calculated by adding 280 days to the LMP date.

For ultrasound dates, the calculation is similar but uses the date of the ultrasound as the starting point. The ultrasound date is typically around 12-14 weeks into the pregnancy, so the due date is calculated by adding the remaining weeks to the ultrasound date.

Understanding Pregnancy Weeks

Pregnancy is divided into three trimesters, each lasting about 13 weeks:

• First Trimester (Weeks 1-13): The foundation of the baby is established, including major organs and limbs.
• Second Trimester (Weeks 14-27): The baby grows rapidly, and the mother may start showing her pregnancy.
• Third Trimester (Weeks 28-40): The baby prepares for birth, and the mother's body makes final preparations.

Tracking your pregnancy in weeks helps you understand the stages of development and what to expect during each trimester.

Example Calculation

Let's say your last menstrual period (LMP) was on January 1, 2024. Using our calculator:

1. Select "Last Menstrual Period (LMP)" as the calculation method.
2. Enter January 1, 2024.
3. Click "Calculate".

The calculator will show that your due date is October 31, 2024, and you are currently in week 1 of your pregnancy.