Due Date Calculator Pregnancy Birth and Baby

How to Use This Calculator

Using our due date calculator is simple. You can calculate your due date in two ways:

1. Using your last menstrual period (LMP): Enter the first day of your last menstrual period. The calculator will add 280 days (40 weeks) to this date to estimate your due date.
2. Using an ultrasound date: If you've had an ultrasound, enter the date of the ultrasound and the number of weeks your baby was determined to be at that time. The calculator will add the remaining weeks to estimate your due date.

The calculator will display your estimated due date, the pregnancy timeline, and baby development stages. You can also view a chart showing the pregnancy timeline and important milestones.

How the Due Date Calculation Works

The due date calculation is based on the average length of a full-term pregnancy, which is 40 weeks (280 days) from the first day of the last menstrual period (LMP).

If you've had an ultrasound, the calculation is slightly different. The calculator will add the remaining weeks to the ultrasound date to estimate your due date.

Keep in mind that these calculations are estimates. Your actual due date may vary by a few days or weeks.

Understanding the Pregnancy Timeline

The pregnancy timeline is divided into three trimesters, each with its own unique milestones and developments.

First Trimester (Weeks 1-12)

During the first trimester, your baby's major organs and body structures are forming. You may experience morning sickness, fatigue, and frequent urination.

Second Trimester (Weeks 13-28)

In the second trimester, your baby's growth accelerates. You may notice your baby moving more, and your belly may start to show. This is often when many women have their first ultrasound.

Third Trimester (Weeks 29-40)

The third trimester is when your baby prepares for life outside the womb. You may experience Braxton Hicks contractions, back pain, and shortness of breath. This is also when you'll start preparing for labor and delivery.

Baby Development Stages

Each week of pregnancy brings new developments for your baby. Here are some key milestones:

• Weeks 1-4: Your baby's major organs and body structures are forming. At this stage, your baby is about the size of a grain of rice.
• Weeks 5-8: Your baby's heart is beating, and their fingers and toes are forming. Your baby is now about the size of a lime.
• Weeks 9-12: Your baby's eyes, ears, and nose are developing. Your baby is now about the size of a plum.
• Weeks 13-16: Your baby's movements are becoming more pronounced, and their bones are hardening. Your baby is now about the size of a banana.
• Weeks 17-20: Your baby's lungs are developing, and their brain is growing rapidly. Your baby is now about the size of a bell pepper.
• Weeks 21-24: Your baby's reflexes are developing, and their skin is becoming less transparent. Your baby is now about the size of a large carrot.
• Weeks 25-28: Your baby's bones are becoming more defined, and their fat stores are increasing. Your baby is now about the size of a small squash.
• Weeks 29-32: Your baby's movements are becoming more active, and their eyes are opening. Your baby is now about the size of a large sweet potato.
• Weeks 33-36: Your baby's lungs are maturing, and their brain is developing rapidly. Your baby is now about the size of a small pumpkin.
• Weeks 37-40: Your baby is preparing for life outside the womb. Their bones are fully formed, and their brain is developing rapidly. Your baby is now about the size of a large watermelon.

Important Pregnancy Dates

In addition to your due date, there are several other important dates to keep in mind during your pregnancy:

• Conception Date: The date you conceived your baby, calculated by subtracting 14 days from your first day of your last menstrual period.
• First Trimester Ultrasound: Typically scheduled between 11 and 14 weeks of pregnancy.
• Second Trimester Ultrasound: Typically scheduled between 20 and 22 weeks of pregnancy.
• Third Trimester Ultrasound: Typically scheduled between 32 and 34 weeks of pregnancy.
• Antepartum Care Visits: Regular check-ups with your healthcare provider throughout your pregnancy.
• Non-Stress Test: A test to monitor your baby's heart rate and movement, typically performed between 28 and 34 weeks.
• Glucose Tolerance Test: A test to screen for gestational diabetes, typically performed between 24 and 28 weeks.
• Group B Streptococcus (GBS) Screening: A test to screen for a bacterial infection, typically performed between 35 and 37 weeks.