man and woman looking at pregnany scan

Pregnancy Due Date Calculator

Wouldn’t it be wonderful if we could accurately predict when your little bundle of joy will arrive? Calculating your baby due date can be so confusing to figure out- so many numbers to crunch, days to add or days to subtract.  Our pregnancy due date calendar is exactly what you need to make it easy!

How to use our Pregnancy Due Date Calculator

Our Pregnancy Due Date Calculator is a fun tool you can use to get an estimated baby due date for your baby's arrival. All you need to do is type in the date of your last period into the pregnancy calculator below, and the due date calculator will do the rest! 

Although babies rarely stick to a schedule, usually a full-term baby will arrive anywhere from 37 to 42 weeks from your conception date. Ovulation, when your body releases an egg from your ovaries, happens approximately 2 weeks after the start of your last period, this is the time you conceive, or fall pregnant. As it’s difficult to know your ovulation and conception date exactly, most baby due date calculators, like our Pregnancy Due Date Calculator below, use the first day of your last period, and add 280 days (40 weeks) to that day, to estimate your baby due date. 

Menstrual cycles can vary, so keeping track of your menstrual cycle will help you identify the date of your last period. If you haven’t been tracking your periods, it’s all good, make an educated guess based on an average 28 day cycle, and the due date calculator will give you your baby due date based on this best guess.  If you are on an IVF journey, your healthcare professional will be able to provide you with the date to use in a pregnancy due date calculator, for example the date of egg fertilisation, or date of embryo transfer.

To get a more accurate baby due date, an ultrasound conducted by your doctor will be able to confirm your baby’s age and estimated due date.

Note: The methods used by this application are based on an estimation taking into account information provided by the user and scientific knowledge/understanding in this area. This information is general in nature and it is not intended as medical advice or services. The use of this application does not replace any formal advice from your doctor or healthcare provider and you should consult your doctor for medical advice. The use of this application is at the entire discretion of the user and the user assumes any risk associated with using this application.

What was the first day of your last period?

User will most likely use this feature mainly on mobile. Therefore touch events and date picker etc.


  • The first day of last period is calculated as the first day your period started when you had your very last period.  This isn’t always easy to remember unless you’ve been tracking your periods. 
  • Conception date is the day your egg is fertilised with sperm. It is the start of your pregnancy journey.
  • Menstrual cycle is a natural process, controlled by hormones, that prepares a woman’s body to fall pregnant. It is measured from the first day of your last period to the first day of your next period.
  • Ovulation is a phase of the female menstrual cycle, when the ovaries release an egg, in preparation for being fertilised by sperm, and becoming pregnant.
  • An Ultrasound offers a safe way of checking in on your little lodger. It uses harmless soundwaves to create images of your baby while they are in your womb, that your healthcare professional can review to get more information about your baby, including their age and estimated due date.
Popular FAQs Icon
How many weeks pregnant am I?
Pregnancy FAQs

Weeks of pregnancy start from the day of conception. To know how many weeks pregnant you are, you would need to know the date of conception, and simply count the number of weeks from that day.  It’s quite common that you may not know the exact date of conception, and in this case the counting usually starts from the first day of your last period, and add 40 weeks (280 days) to this date to get your estimated due date.

When am I due?
Pregnancy FAQs

On average, a full-term pregnancy lasts between 37-42 weeks. If you know your conception date, you can calculate the estimated due date by counting 37-42 weeks after the conception date. This will give you a baby due date range.  Most pregnancy due date calculators will use 40-41 weeks as full-term, which is the midpoint of 37-42 weeks.

How do doctors calculate due date?
Pregnancy FAQs

Doctors can provide an estimated baby due date by either counting the number of weeks from conception, or performing an ultrasound of your baby which will be able to more accurately predict your baby due date based on their size.

How do you calculate due date without the last period?
Pregnancy FAQs

If you don’t know the date of your last period, or you are finding it difficult to estimate, you can ask your doctor for an ultrasound to help calculate your baby's due date. An ultrasound offers a safe way of checking your baby’s size and from this your doctor can predict their age and when they are due.