Your Pregnancy Due Date Calculator

Pregnant woman calculating her due date

Your pregnancy is officially counted from the first day of your last menstrual period (LMP), with most pregnancies lasting to around 40 weeks. The easiest way to calculate your estimated due date (EDD) is to count 40 weeks, or 280 days, from the first day of your LMP.

Instead of getting out your calendar, use our simple pregnancy calculator, below, to calculate your EDD based on your LMP.

Due Date Calculator
When did your last period start?
Generally, how long are your cycles?
Calculate your due date
Your baby is likely to be born on or around*
*Only your physician can accurately determine your due date or the date of your conception based on his/her knowledge of your complete medical condition.
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In partnership with Clearblue®.

On average, conception occurs two weeks after your last period but it can vary from person to person, so you can also count 266 days from conception if that date is known (from ovulation testing or the date of insemination, for example).

Once you have discovered and confirmed your pregnancy, you’ll need to find a lead maternity carer to care for you and your pēpi during your pregnancy. See our guide to your options for choosing a lead maternity carer in New Zealand here. The majority of pregnant people in New Zealand choose to be looked after by a lead maternity carer midwife who is a registered and practicing member of the New Zealand College of Midwives. They provide free care for normal pregnancy and birth. To find an available midwife in your area, visit Keep in mind that midwives in New Zealand book up quickly so it’s important to find an available LMC as soon as possible and to let them know your due date when you message them.

Note: If a due date is later calculated from an ultrasound dating scan, this date is usually preferred by an LMC as it is gives an accurate measurement for the current gestational age.