Due Date for Baby Calculator

Pregnancy due dates are important for planning and preparation. This calculator helps you determine your estimated due date based on your last menstrual period (LMP) or ultrasound date.

How to Use This Calculator

To calculate your due date:

Enter your last menstrual period (LMP) date or ultrasound date
Select whether you're using LMP or ultrasound date
Click "Calculate Due Date"
Review your estimated due date and pregnancy timeline

For most accurate results, use your first day of your last menstrual period. If you had an ultrasound, use the date from that exam.

How Pregnancy Due Dates Are Calculated

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

For ultrasound dates, the calculation is based on the gestational age at the time of the ultrasound plus the date of the ultrasound.

Due Date = LMP Date + 280 days or Due Date = Ultrasound Date + (40 weeks - Gestational Age)

The calculator uses this formula to determine your estimated due date. The result is an estimate and may vary from your actual due date.

Example Calculation

If your last menstrual period started on January 1, 2023:

LMP Date: January 1, 2023
Adding 280 days: January 1, 2023 + 280 days = October 7, 2023

Your estimated due date would be October 7, 2023.

Remember, this is an estimate. Your actual due date may vary by several days.

Frequently Asked Questions

How accurate is the due date calculator?

The calculator provides an estimate based on standard pregnancy length. Actual due dates may vary by several days.

Can I use this calculator if I had an ultrasound?

Yes, select "Ultrasound Date" and enter your gestational age at the time of the ultrasound.

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

If you had an ultrasound, you can use that date. Otherwise, you may need to estimate your LMP date.

When should I see a doctor about my due date?

If your due date is approaching and you haven't had your baby, contact your healthcare provider.