Due date calculator

Have you been trying to work out your pregnancy due date and found yourself adding, subtracting, multiplying and counting on your fingers? It can be confusing, whether your baby is due 34 or four weeks from today! Luckily, our handy pregnancy due date calculator can help you easily find out when your baby is due.

How is my pregnancy due date calculated?

Unless you've been tracking your ovulation, there's no way to know for sure exactly when you ovulated and conceived. That's why your due date is calculated based on the date of your last period instead.

Most women ovulate about two weeks after the first day of their period, and conceive shortly afterwards. The average pregnancy lasts between 37 weeks and 42 weeks. Our calculator uses this information to give you an estimated due date.

Will my baby definitely be born on my due date?

Unfortunately, no one can say for sure exactly when your baby will arrive. In fact, only about four per cent of babies are born on their due date! But it is likely that your baby will arrive in the few weeks either side of your estimated due date. Knowing this can help you to be prepared for labour and birth, and to have everything ready for your new baby.

Will my due date change when I have a scan?

It may do. Your first pregnancy scan will probably happen when you're between 10 weeks and 14 weeks pregnant. It's known as the dating scan, and is used to give you a more accurate due date, based on the size and development of your baby. Learn more about antenatal scans.

Check out our week by week information from the start of your pregnancy:

• Your pregnancy at 2 weeks
• Your pregnancy at 3 weeks
• Your pregnancy at 4 weeks