Due Date Calculator from UPMC in Central Pa.

Congratulations! Now that you’re pregnant, you’re probably wondering when your baby will make his or her appearance. Our due date calculator can help you figure out when to expect your new bundle of joy.

A typical pregnancy lasts about 280 days – or 40 weeks – starting with the first day of your last normal menstrual period. There are three steps you need to follow to determine your estimated due date (EDD):

1. Determine the first day of your last menstrual period
2. Count back three calendar months from the first day of your last menstrual period
3. Add one year and seven days to that date

Here’s an example: Say your last menstrual period began on September 9, 2014. Count back three calendar months to June 9, 2014. Add one year and seven days to arrive at your EDD of June 16, 2015.

This three-step due date calculator is referred to as Naegele's Rule and is based on a normal 28-day menstrual cycle. Dates may have to be adjusted for longer or shorter menstrual cycles. However, even with adjustments, less than 10 percent of women actually give birth on their calculated due dates. Delivery two weeks before or after the estimated due date is still considered normal.

In cases where the date of conception is known precisely, such as with in vitro fertilization, the EDD is calculated by adding 266 days to the date of conception.

Interactive Due Date Calculator

Our due date calculator can help you figure out when to expect your new bundle of joy.

Need more information?

Phone: 717-231-8900 

Learn more about Prenatal and Maternity Services at UPMC in central Pa.

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Resources

• Online Maternity Patient Pre-Registration Form
• Downloadable Maternity Patient Pre-Registration Form