When My Baby Is Due Calculator

Pregnancy due dates are calculated based on either your last menstrual period (LMP) or your ultrasound date. This calculator helps you determine your estimated due date using the standard 40-week pregnancy period.

How to Use This Calculator

To calculate your due date:

Select whether you want to calculate based on your last menstrual period (LMP) or ultrasound date.
Enter the date of your last menstrual period or ultrasound date.
Click "Calculate" to see your estimated due date.

The calculator will display your estimated due date and the range of dates you should expect to deliver your baby.

How the Due Date Calculation Works

Pregnancy is typically considered to be 40 weeks long, from the first day of your last menstrual period (LMP) to the estimated due date. The due date is calculated by adding 40 weeks to the first day of your last menstrual period.

For example, if your last menstrual period started on January 1, 2023, your due date would be October 31, 2023.

Formula: Due Date = Last Menstrual Period + 40 weeks

If you have an ultrasound date, the calculation is similar. The ultrasound date is typically around 20 weeks into the pregnancy. The due date is calculated by adding the remaining weeks to the ultrasound date.

Formula: Due Date = Ultrasound Date + (40 weeks - Ultrasound Weeks)

The calculator uses these formulas to provide your estimated due date and the range of dates you should expect to deliver your baby.

Example Calculation

Let's say you had your last menstrual period on March 15, 2023. Using the calculator:

Select "Last Menstrual Period" as the calculation method.
Enter March 15, 2023 as the date.
Click "Calculate".

The calculator will display your estimated due date as December 23, 2023, with a range of dates from December 16, 2023 to December 30, 2023.

Note: The actual due date may vary by a few days from the estimated date. Always consult with your healthcare provider for the most accurate information.

Frequently Asked Questions

How accurate is the due date calculator?

The due date calculator provides an estimate based on standard pregnancy lengths. The actual due date may vary by a few days. For the most accurate information, consult with your healthcare provider.

Can I use the calculator if I had an ultrasound?

Yes, you can use the calculator with your ultrasound date. Select "Ultrasound Date" as the calculation method and enter the date and the number of weeks into the pregnancy.

What if I don't know my last menstrual period date?

If you don't know your last menstrual period date, you can use the calculator with your ultrasound date. The calculator will provide an estimate based on the ultrasound date and the number of weeks into the pregnancy.