Pregnancy Calculator

Pregnancy Calculator - How Many Weeks Are You?

Think you may be pregnant but dont know your due date or which week of your pregnancy you are in? Enter the date of your last menstrual period and the number of days in your menstrual cycle into the pregnancy calculator to calculate your estimated due date, concetion date and your estimated pregnancy week.

PREGNANCY CALCULATOR - Calculate Your Due Date

Remember, the more you know about your own monthly cycle the more accurate the calculator will be. If you are trying to fall pregnant, read our section on getting pregnant.

First Day Last Menstrual Period
Average Length of Cycle (Default 28 )
*(22 to 45)
Average Luteal Phase Length (Default 14 )
(Ovulation Period)
*(9 to 16)
Your Estimated Conception Date:
Your Estimated Due Date:
Estimated Pregnancy Week:

How Do You Calculate Your Due Date?

Have you ever wanted to know how your doctor or health care provider calculates your estimated due date and age of your baby? Well, it is actually a really simple process:

You add 280 days to the first day of your last menstrual period, or LMP

It is really as simple as that. The 280-day cycle works on the typical 266-day gestation period for humans. We get 280 days because we add 14 days, which is the average time span for when you would have ovulated.

Obviously this is just an average, but with our calculator the 14 days can be changed for what your actual Luteal Phase, or to what your actual ovulation period actually is, and this makes it extremely useful, as the more you know about your monthly cycle, the more accurate your calculations will be.

The more you know about your monthly cycle the more accurate our calculator will be. So as mentioned in the conception basics, it is a good idea to track your monthly cycles for a few months before hand.

Of course not all pregnancies are planned, but if your monthly cycle is more regular, then you should have no problems using our calculator.

Don't forget that you can use these calculations in conjunction with our pregnancy calendar.

Your Pregnancy In Pictures

See what your baby looks like each week as your pregnancy develops with a series of images and artist impressions from the womb. Take a look inside your womb here.

Please note: The information provided on this website is not intended to and do not constitute professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website.