Baby Conception Date Calculator Due Date

Pregnancy dates are important for planning and tracking your baby's development. This calculator helps you determine your conception date and estimated due date based on your last menstrual period (LMP) or ultrasound date.

How to Use This Calculator

To calculate your pregnancy dates:

Enter your last menstrual period (LMP) date or ultrasound date
Select whether you're using LMP or ultrasound date
Click "Calculate" to see your estimated conception date and due date

The calculator uses standard pregnancy calculations where a full-term pregnancy is considered 40 weeks (280 days) from conception.

How Pregnancy Dates Are Calculated

Pregnancy dates are typically calculated based on either:

Last Menstrual Period (LMP): The first day of your last menstrual period
Ultrasound Date: The date of your first trimester ultrasound

Formula for Due Date Calculation

If using LMP date:

Due Date = LMP Date + 280 days (40 weeks)

If using ultrasound date:

Due Date = Ultrasound Date + (280 days - (weeks since conception × 7 days))

The calculator accounts for the fact that pregnancy is typically calculated from the first day of the last menstrual period, not the actual conception date.

Example Calculation

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

Conception Date: Approximately January 14, 2023 (14 days after LMP)
Due Date: October 31, 2023 (280 days after LMP)

This example shows the standard 40-week pregnancy calculation.

Important Pregnancy Dates

Here are some key dates to remember during pregnancy:

Weeks	Development Stage	Key Milestones
1-4	Germinal	Implantation, early organ formation
5-12	Embryonic	Major organs forming, heart begins to beat
13-27	Fetal	Fingers and toes forming, baby can hear and taste
28+	Full-term	Baby is ready for birth

Frequently Asked Questions

How accurate is the pregnancy date calculator?

The calculator provides an estimate based on standard pregnancy calculations. For precise dates, consult your healthcare provider.

Can I use this calculator if I had an ultrasound?

Yes, you can enter your ultrasound date and the number of weeks since conception to get a more accurate due date.

What if my period was irregular?

The calculator uses your last menstrual period date as a reference point. If your cycle is irregular, consult your healthcare provider.

How do I know if I'm pregnant?

Common signs include missed periods, nausea, breast tenderness, and frequent urination. For confirmation, take a pregnancy test.