DUE DATE CALCULATOR
Enter the first day of your last period and find out when your baby is due.
Pregnancy Due Date Calculator
Use the drop-down menu to calculate your due date or current weeks of pregnancy.
How is my due date calculated?
Your due date is calculated from the first day of your last period.
The most common way to calculate your due date is by counting 40 weeks or 280 days from the first day of your last menstrual period (LMP). And that’s how your midwife, and healthcare provider will do it as well.
This method is based on the idea that women generally ovulate about 2 weeks after their period starts and pregnancy typically lasts about 38 weeks from conception. Plus it’s usually easier to remember when your period started than to figure out what day you conceived.
Conception date
If you happen to know the day you conceived, add 38 weeks from that date to calculate your due date. You can tell when you conceived if you know when you ovulated -- say, if you were using an ovulation predictor kit or tracking your ovulation symptoms.
Note: Because sperm can live for up to 5 days inside your body, you don't necessarily conceive on the day you have sex. As such up to 5 days after you have sex that you may ovulate and release an egg that gets fertilised by a waiting sperm. That’s the day you conceive.
Can my due date change?
Your healthcare provider might revise your due date if your baby is measured during a first trimester ultrasound and found to be much bigger or smaller than expected. This is more likely to happen if you have an irregular cycle that makes it hard to pinpoint the date of conception.
How likely am I to give birth on my due date?
Your due date is just an estimate. Only 1 in 20 women delivers on her due date. You're just as likely to give birth within the two weeks before or after.
Find out your due date with our pregnancy calculator, plus get all the info you need about your developing baby and see how big your baby is right now with our weekly pregnancy guide and sign up to our email newsletter for week by week pregnancy and new baby emails.
Our calculator uses the method most healthcare providers will use to determine your expected delivery date (EDD), once you've confirmed your pregnancy
Your EDD is 40 weeks from the first day of your last period, although your baby was probably conceived about two weeks after that.
If your baby arrives on your EDD, your baby is only 38 weeks old - this is because your period and ovulation are counted as the first 2 weeks of pregnancy.
Your calculated due date is only an estimate - most babies are born between 38 -42 weeks.
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