If you are confirmed pregnant and are anxious to know the due date of your baby, then you have landed at the right place. Here is a calculator that will answer your question at the click of a button. It is a simple calculation based on a single parameter. If complicated charts are leaving your more anxious than you began with then this is time to switch to a straight and simple way of knowing your expected date of delivery.
A pregnancy due date calculator is a tool which displays the expected date of delivery. The only requirement of this tool is the date of first day of the last menstrual period. The calculator works on the  estimate that pregnancy lasts fro 40 weeks from the last menstrual period. So when you input that date, the calculator adds 40 weeks or 280 days to it and gives you the exact date from there on.
How to Use the Calculator?
The calculator here has a ‘Date bar’ that enables you to enter the first day of the last menstrual period. Follow the steps as under:
1. Click the cursor in the date bar and enter the date in the mm/dd/yyyy format.
2. Having done that Click on the submit button below the bar.
3. This will take you to a screen that displays the expected due date and also tells you how the  calculation happened.
4. If you need to recalculate then click on the recalculate button on the screen and it will take you back to the previous screen.
5. The site also provides the option to print your results.
The calculator is based on a mathematical formula that calculates the results based on your inputs. Hence the results are as accurate as your inputs. Also, the length of the menstrual cycles may vary from woman to woman and may not always be 28 days long. In which case, the number may have to be adjusted accordingly. Finally, before going ahead keep in mind that most women do not deliver the baby on dot. This is an estimate and the baby can arrive a few days before or after this date.