This calculation is again fairly straight forward.

The problem with this method is that it does not take into account, 
women's longer or shorter menstruation cycle.

Step 1. Enter the date of the first day of the last menstruation period:

Step 2.              

The calculation results are shown in the table below:

First day of last Menstruation Period

Estimated (on or about) Due Date

If it's so, then your Baby's Birth Segment would be: