Perhaps the most common reaction to finding out that you're pregnant is 'Congratulations!', quickly followed by the question, 'When is the baby due?'

In general, babies should be born 9 months once they're conceived- but that's a wide estimate. To find out your exact due date you can look it up using a due date calculator.

A Quick Guide on How to Use a Due Date Calculator

To get started, you will need to determine the first day of your last menstrual period. This will be the gestational age, which is generally more accurate than knowing the date of conception.

For those that have 28-day menstrual cycles, you can compute for when you're going to pop using two methods- an online calculator or via Naegele's rule, and by means of a pregnancy wheel.

Online Due Date Calculator

Since most people have access to the internet nowadays, an online due date calculator can provide a convenient way to know when you're going to have the delivery.

Using it can be as simple as entering the required date. The tool will provide an approximate timeline by adding 40 weeks or 280 days on when you had your last menstrual period and taking into factor the cycle.

An online calculator will take into consideration the ovulation and period. Some will ask for the date of conception but then most women wouldn't know unless they specifically noted it down.

Naegele's Rule

You can do Naegele's Rule by adding 7 days to your first day of LMP, then minus three months.

Most pregnancies will last 40 weeks, or 280 days starting with the last menstrual period date. You can determine when you're going to pop with these 3 steps.

Step 1. Know the first day of the last menstrual period.

Step 2. Count 3 months back from that day.

Step 3. Add 7 days and a year.

Keep in mind that Naegele's Rule determines the due date for women who follow a 28 day cycle, and will need to be adjusted for those who follow shorter or longer menstrual cycles.

Pregnancy Wheel

A pregnancy wheel is a pre-determined due date calculator where you just have to know your LMP.

Most doctors use this because it's easy and doesn't require too much math. When the LMP is determined they just have to line up the date via the indicator, and then the due date is displayed. It's relatively simpler than the other methods but it works.

Calculators and Pregnancy Monitoring- Is My Due Date Accurate?

While it's difficult to estimate the exact date of conception, a lot of women have trouble pegging their exact LMP down.

When this happens, you can compute the due date the following ways:

- If you didn't know the LMP in a certain week, your doctor can help collect more information then figure out the due date.

- If you didn't know when you had your last period, an ultrasound can check for the due date.

Keep in mind that the LMP works only for those who have a regular 28-day menstrual cycle. It's important to have a reliable EDD, or estimated delivery date so you can expect to go in labor and not be caught off-guard.

An ultrasound can be an accurate tool to check the age of your baby during the early stages. Accuracy drops off as time goes on as fetal growth varies from one mother to another. Your doctor can order an ultrasound to check the CRL, or crown rump length and use this to determine the baby's age during the first trimester.

A sonogram image can serve as a timeless memento on a joyous occasion. To preserve and highlight this memory you can get our lovely pregnancy keepsake picture frame as a wonderful souvenir.

Calculating when you're going to pop isn't wholly accurate. There's only a small percentage who actually delivers on their due date. Its main purpose is to prepare would-be mothers and give them estimated dates on the most important events- pregnancy, labor, and delivery.

The bottom line is that a due date only serves as an estimate. Your baby may come in earlier or later, and only when they're ready. To this end, it's best to check in with your doctor regularly.