Pregnancy Due Date Calculator

How is Due Date Calculated?

This calculator uses Naegele's Rule, which is the standard method used by doctors worldwide to estimate the delivery date (EDD). It assumes a pregnancy lasts for 280 days (or 40 weeks) from the first day of your last period.

Our calculator also adjusts for your Cycle Length. If your cycle is longer than 28 days, your due date is pushed later. If it's shorter, the date is earlier.

Understanding Trimesters

A pregnancy is divided into three stages called trimesters:

• First Trimester (Week 1 - 12): The baby's body structure and organ systems develop. Most miscarriages occur during this period.
• Second Trimester (Week 13 - 26): Often called the "golden period" as morning sickness usually fades. You may start to feel the baby move.
• Third Trimester (Week 27 - 40): The baby grows rapidly in weight and prepares for birth. You may feel more uncomfortable due to the size of the belly.

Frequently Asked Questions (FAQs)

Q. How accurate is this calculator?

It is an estimate. Only about 5% of babies are born on their exact due date. Most babies arrive within a window of two weeks before or after the due date (between week 38 and 42).

Q. Why ask for "Last Period" instead of "Conception Date"?

Most women know when their period started, but it's very hard to know the exact day conception (fertilization) happened. That's why medical standards count pregnancy from the first day of the Last Menstrual Period (LMP).

Q. What if I have irregular periods?

If your periods are very irregular, Naegele's rule might not be accurate. In that case, an early ultrasound scan (dating scan) by your doctor is the most reliable way to determine how far along you are.