Pregnancy Due Date Calculator
- 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.
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.
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.
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.
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.