Due Date Calculator

The chance of your baby being born on its due date is less than one in twenty!

A single estimated day of delivery only tells a tiny part of the story. Our due date calculator shows graphically on which due dates your baby is most likely to be born. Discover how likely your baby is to be born early or late.

Greater accuracy

Using the latest medical research, we work out your baby's expected due date of delivery (EDD) more precisely using a proprietary and patent-pending algorithm. We take into account important factors which determine the length of your pregnancy which other online calculators ignore, such as the length and regularity of periods, maternal age, background and number of previous children.

It is fun, easy and free to use. Try it now!

Discover famous people and important calendar events connected with your child’s likely birthday, along with star signs. Baby names have never been so easy or so much fun to find

Plan your pregnancy

We'll support you with valuable information throughout your pregnacy, week by week. And, once your child is born, redbabybook offers the most personal and sophisticated baby book on the web, in which to store and track your child's development.
See an example of it in action here

Go back

Due Date Information Help

Enter the date of the first day of your last menstrual period or if you have been given a due date please enter it here Predictions from scans at around 12 weeks are extremely accurate Use the calendar to select your date by clicking on the correct day, if you need a date in previous months just click the arrow in the top left to go back a month Enter the average number of days between the start of your periods. If your periods are irregular use the average 28 day cycle The advanced calculation uses the latest medical research to produce a more accurate due date calculation for natural spontaneous delivery, tailored to your circumstances. If you select the standard option we employ a simpler method often used by more primitive calculators Whether your period is regular or irregular has a statistical impact upon the likely birth date of your child. Please select the applicable option Maternal age does have an impact upon the likely birth date of a child. Please select your age group from the menu Enter the number of children you have had before since this has a significant effect on the likely birth date This is not compulsory. Enter the ethnicity of the mother here. Although this might appear to be an intrusive question it does have significant effect on the due date This is not compulsory. Enter the ethnicity of the father here. Although this might appear to be an intrusive question it does have significant effect on the due date

Your Due Date Information

I know my..
First day Due date Date
Please enter a valid date
Calculation method
Are your periods...
Cycle length
Mother's age
Is this your...
Ethnicity of Mother
Ethnicity of Father