A Baby Due Date Calculator

Determining your baby's due date is an important part of pregnancy planning. Our due date calculator helps you estimate when your baby is expected to be born based on your last menstrual period (LMP) or ultrasound date.

How to Use This Calculator

To calculate your due date, you'll need either:

Your last menstrual period (LMP) date, or
An ultrasound date and the estimated gestational age at that time

Note: The due date calculator provides an estimate. Actual delivery dates can vary by several days.

Using the calculator is simple:

Enter your last menstrual period (LMP) date in the first field
Click "Calculate" to see your estimated due date
Review the pregnancy milestones based on your due date

For more accurate results, especially in the first trimester, consider getting an ultrasound to determine your exact gestational age.

How the Due Date is Calculated

The standard calculation for due date is based on a 280-day average pregnancy length, which is calculated as:

Due Date = Last Menstrual Period (LMP) + 280 days

For example, if your LMP was on January 1, 2023:

Adding 280 days would give you November 6, 2023
Subtracting 40 weeks (280 days) from November 6 gives you January 1, 2023

This calculation assumes a full-term pregnancy of 40 weeks. Some healthcare providers may use slightly different calculations based on specific clinical guidelines.

Remember: The due date is an estimate. Many babies are born within 2 weeks before or after the calculated date.

Pregnancy Milestones

Once you have your due date, you can track your pregnancy progress using these general milestones:

Weeks	Milestone
1-4	Implantation and early development
5-8	Organ formation begins
9-12	Fetal movement may be felt
13-16	Fetal heart can be heard
17-20	Quickening - first fetal movements
21-24	Baby's bones start forming
25-28	Baby's face begins to form
29-32	Baby's fingers and toes develop
33-36	Baby gains weight rapidly
37-40	Full-term pregnancy

These milestones are general guidelines. Every pregnancy is unique, and individual development may vary.

Common Questions

Here are answers to some frequently asked questions about due dates:

How accurate is the due date calculator?

The calculator provides an estimate based on average pregnancy length. Actual delivery dates can vary by several days. For more precise timing, consider getting an ultrasound.

Can I use this calculator if I had an ultrasound?

Yes, you can use the ultrasound date and estimated gestational age to calculate your due date. Simply subtract the weeks from your due date.

What if I'm having twins or multiples?

For multiple pregnancies, the due date is typically calculated based on the earliest estimated due date of the babies.

Should I use this calculator for medical advice?

No, this calculator provides estimates only. Always consult with your healthcare provider for medical advice and timing.