Due Date Calculation

Are You Pregnant? Congratulations!

Use the due date calculator by entering the first day of your last period. If you don't know the exact date, calculate as close as possible. Then enter your average length cycle, the average luteal phase length if you know it and then click "Calculate!"

Happy Due Date Calculation!

Last Menstrual Period:

 (MM/DD/YYYY format)

Average Length of Cycles: (22 to 45)

 (defaults to 28)

Average Luteal Phase Length: (9 to 16)

 (defaults to 14)



Estimated Conception: 

Estimated Due Date:    

Estimated Fetal Age:    

  

When Will My Baby Come?

Every baby and every woman is different, so what you get is a very close estimate. In my homeopathy practice, women give birth mostly when they are ready and when they feel mentally and emotionally loved and protected. The due date is more for medical reasons so that your doctor will know if the baby is growing accordingly and if you are gaining weight as you should.

How is the Due Date Calculation Done?

The due date calculation is done by using the first day of your last menstrual period (LMP). You have to keep in mind that other factors may also play a role in determining your due date because you may not have ovulated exactly on day 14 of your cycle. Also, not necessary you conceived on the same day you had intercourse. You could have conceived up to 5 days after because spermatic cells can survive in the uterus for all this time. LMP is used because it is the most reliable and certain date you have in order to measure the likely date of conception, but if you ovulated late or your periods are irregular, the estimation cannot be as accurate. That is why many physicians or midwives recommend a dating ultrasound when in doubt.

The Lunar Calendar

In ancient times women used the different phases of the moon to determine the baby's arrival date. When I was overdue for all my three pregnancy, my doula told me to count how many times the moon was in the phase of my missed period. At the 10th time the moon entered into the phase of the missed period, the baby is due. Every time right at 41 weeks each one of my baby was born!

Medical Due Date Calculation

The due date calculation is usually based on that fact that fertilization occurs 14 days after the last menstrual period if you consider the average 28 days menstrual cycle. Thus, the average duration of a woman's pregnancy, also called gestational period, is calculated by subtracting 14 days from 280 days giving the result of 266 days.

Learn More: