Pregnancy Due Date Calculator

Calculate your estimated due date based on last menstrual period or conception date. See trimester timeline.

Calculate From

First Day of Last Period

How to Use the Due Date Calculator

Select whether you want to calculate from your last menstrual period (LMP) or from the date of conception. Enter the date, and the calculator will estimate your due date, current week of pregnancy, trimester, and key milestone dates throughout your pregnancy.

Understanding Your Due Date

Your estimated due date (EDD) is the date your baby is expected to arrive. Pregnancy typically lasts about 40 weeks from the first day of your last period, or 38 weeks from conception. Remember that the due date is an estimate, and healthy babies can arrive anytime between 37 and 42 weeks.

Frequently Asked Questions

How is the due date calculated?

The most common method is Naegele's rule: add 280 days (40 weeks) to the first day of your last menstrual period (LMP). If using conception date, 266 days (38 weeks) are added instead.

How accurate is a due date calculator?

Due date calculators provide an estimate. Only about 5% of babies are born on their exact due date. Most births occur within 2 weeks before or after the estimated date. Your doctor may adjust the date based on ultrasound measurements.

What are the trimesters of pregnancy?

The first trimester spans weeks 1-12, the second trimester weeks 13-26, and the third trimester weeks 27-40. Each trimester involves different stages of fetal development and maternal changes.

When should I see a doctor after finding out I'm pregnant?

Schedule your first prenatal visit between 6-8 weeks of pregnancy. Contact your healthcare provider as soon as you get a positive pregnancy test to schedule an appointment.