Pregnancy Due Date Calculator

When was the first day of your last period?

For example, 15 12 2019

An image illustrating the step-by-step process of using a Due Date Calculator. The image shows a user entering the date of their last menstrual period (LMP) into the calculator's input field. The next step displays the user clicking on the 'Calculate' button and the calculator generating an estimated due date for their pregnancy. This image visually guides the user on how to use the Due Date Calculator tool, which helps individuals determine an approximate date for the arrival of their baby based on the start date of their last menstrual period. It is a helpful tool for expectant parents to track the progress of their pregnancy and plan accordingly.

Finding out you are pregnant leads to many questions and planning considerations. One of the first things you want to figure out is your estimated due date. Read on for a simplified guide to pregnancy due date determination.

What is a Due Date?

Your pregnancy due date, also called the estimated date of delivery (EDD), is an approximation of when you will give birth. Doctors typically measure 280 days (40 weeks) from the first day of your last menstrual period (LMP) to predict the due date.

Since this is based on an average 28-day cycle, it may require adjustment if your cycles differ. But it provides a starting estimate to plan around.

Why Confirming a Due Date Matters

Knowing your due date:

  • Helps plan baby preparations like nursery setup, time off work, etc
  • Allows tracking growth progress across trimesters
  • Informs prenatal testing and appointment schedules
  • Indicates when the third trimester and labor may start
  • Ensures you reach full term before delivery

While babies often arrive before or after, having an expected date brings helpful context.

Methods to Estimate Your Due Date

Common ways to calculate your due date include:

  • LMP formula: First day of last period + 280 days
  • Conception calculator: Date of conception + 266 days
  • Obstetric ultrasound: Most accurate, done by weeks 13-26

Track your method to inform your personalized pregnancy timeline.

What to Expect by Trimester

Here is an overview of general due date ranges for each trimester:



Typical Timeframe

Trimester 1

Weeks 1-12

Months 1-3 of pregnancy

Trimester 2

Weeks 13-27

Months 4-6 of pregnancy

Trimester 3

Weeks 28-40

Months 7-9; end of pregnancy

The due date falls in the third trimester - knowing yours helps anticipate labor onset.

How Overdue Can a Pregnancy Be?

Doctors consider a normal pregnancy term to be 38-42 weeks. Most practitioners will induce labor if you go more than 1-2 weeks past your estimated due date rather than letting you go far beyond it.

The risks of placental problems, low amniotic fluid, and poor growth increase substantially each day after week 42. So rather than expect to go very overdue, discuss options for membrane sweeps or medical induction with your doctor as you approach 41 weeks. This ensures delivery happens safely if you don't go into labor naturally by your due date.

What Are The 3 Main Signs Of Labor?

The 3 cardinal signs that labor is likely beginning include:

  1. Contractions - Repetitive tightening sensations from the uterus preparing to dilate the cervix. A timetable pattern indicates active labor.
  2. Rupture of membranes - Breaking of the amniotic sac releasing fluid from the uterus. Also known as water breaking.
  3. Bloody show - Passing of mucus plugs from cervix mixed with blood streaks. Signals cervix is effacing.

When these bodily changes are noticed, even if subtle at first, inform your obstetrician as true labor onset may be underway. Tracking the duration and frequency of contractions helps assess if hospital admission for delivery is needed.

What is the most common week to go into labor?

The most common week for labor to begin is week 40, which is the complete full term of a typical pregnancy. However, normal labor onset falls anywhere between weeks 37-42.

While a small percentage deliver right on their projected due date that was calculated based on the last menstrual period, the peak of the labor distribution curve centers on the 40-week (280-day) mark.

Frequently Asked Questions (FAQs)

Q1: What is a due date in pregnancy?

The due date in pregnancy is an estimated date given by healthcare providers to determine when a baby is likely to be born. 

Q2: How is pregnancy due date determined?

The due date is determined by counting 280 days (40 weeks) from the first day of the woman's last menstrual period. 

Q3: Can the pregnancy due date change?

Yes, the due date can change. Ultrasound measurements taken in early pregnancy can provide a more accurate estimation of gestational age


Calculating your due date using your LMP gives you a target date to anticipate labor and delivery. While predictions based on averages require adjustments, having an initial estimate provides helpful context to track growth milestones. 

Please note, that the calculator is for entertainment only. Consult a medical specialist for accurate assessments.

Read More: How to Calculate Your Due Date

                    How To Use Free Pregnancy Due Date Calculator