How accurate are due date calculators?

Due date calculators provide estimates. Only about 5% of babies are born on their exact due date, with most being born within 2 weeks before or after.

What if I don't remember my last period?

Your healthcare provider can estimate your due date using ultrasound measurements, which are most accurate in the first trimester.

Can my due date change?

Yes, especially early in pregnancy when ultrasound measurements may provide more accurate dating than your LMP.

What's considered full-term?

Full-term is now defined as 37-42 weeks, with early term being 37-39 weeks and late term being 41-42 weeks.

Do first babies come late?

First-time mothers often deliver slightly after their due date, but this varies greatly among individuals.

Due Date Calculator - My Pregnancy Calc

Calculating your due date is one of the first exciting steps in pregnancy. Most pregnancies last about 280 days (40 weeks) from the last menstrual period (LMP), though only about 5% of babies are born exactly on their due date.

How Due Dates Are Calculated

The most common method uses Naegele's rule, which adds 280 days to the first day of your last menstrual period. This assumes a 28-day cycle with ovulation on day 14. Healthcare providers may adjust this based on ultrasound measurements, especially in early pregnancy.

Factors Affecting Due Date Accuracy

Several factors can affect due date accuracy, including irregular menstrual cycles, uncertainty about LMP date, conception through fertility treatments, and individual variations in pregnancy length. First-time mothers often deliver slightly later than the estimated due date.

The Importance of Early Prenatal Care

Early prenatal appointments help confirm and refine your due date through physical exams and ultrasounds. These early measurements are crucial for monitoring proper fetal development and planning appropriate care throughout pregnancy.

Due Date Calculator