Due Date Calculator Pregnancy
Are you counting weeks, months and trimesters? Use our Due Date Calculator to find out your due date or your baby’s expected birthday!

Due Date Calculator

What was the first day of your last period ?

How does the Pregnancy Due Date Calculator Work?

Most normal pregnancies last around 40 weeks or about 38 weeks from conception. The best way to estimate your pregnancy due date is to count 40 weeks from the start of your last period. This is how your care provider will estimate your due date. Do remember that it’s just as normal to deliver a baby a week or two before or after.

Naegele’s rule is a standard way of calculating the due date for a pregnancy. This rule estimates the expected date of delivery (EDD) by adding one year, subtracting three months, and adding seven days to the first day of a woman’s last menstrual period (LMP). For example, say your last period began on May 10. By Adding 1 year and subtracting 3 months we get to February 10th of next year. We then add 7 days to this date – so your pregnancy due date would be February 18.

How else can one calculate the due date?
There are a few additional ways that your care provider might use to determine your EDD and confirm your stage of pregnancy:

  1. Ultrasound: An early ultrasound can more accurately date the pregnancy. Please be aware that not all radiologists / care providers would recommend women to get an early ultrasound. Some practitioners perform ultrasounds routinely, while others only recommend one if your periods are irregular, if you have a history of miscarriages or have other pregnancy related complications.
  2. The size of your uterus : Your practitioner will note the size of your uterus when your initial internal pregnancy examination is performed.
  3. Your fundal height:  The top of your uterus is measured by your gynecologist / obstetrician at each prenatal visit; Your fundus (the upper part of the stomach, which forms a bulge above the level of the opening of the oesophagus) should reach your navel at about week 20, which helps reaffirm your EDD.
  4. Other Pregnancy milestones such as the first time a fetal heartbeat is heard (at about 9 weeks to 12 weeks of pregnancy) as well as when you first feel fetal movement (at about 16 weeks to 22 weeks), can give vital clues to re-calibrate your EDD.

Is the Pregnancy due date calculator always spot on?

The due date calculator is not always accurate. Most studies emphasize that only one in 20 babies is actually born on his or her due date. Since a normal pregnancy often lasts anywhere between 38 to 42 weeks, most infants are born within two weeks either way of your EDD — this keeps most parents guessing their baby’s expected birthday!

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Pregnancy Due Date Calculator was last modified: January 9th, 2017 by Anjali Sharma