Due date calculator
When's your baby making their debut?
How to calculate your estimated due date
Are you pregnant and curious to know your estimated due date (EDD)? Use our EDD calculator to get an estimate.
The most common method to determine your EDD is by calculating from the first day of your last menstrual period. If you don’t remember your last period or if you’ve had IVF, there are alternative methods. In healthcare, an ultrasound can be used to measure the width of the baby’s head (from temple to temple) to estimate the due date.
This dating is usually done either during a first-trimester ultrasound around week 12–13 or at the routine ultrasound in week 18–20. After the ultrasound, your estimated due date may be adjusted to better reflect the baby’s development.
It’s important to remember that babies are typically born between week 37+0 and 42+0, with a high chance of arriving within one week before or up to two weeks after the estimated due date.
Calculate EDD from the last menstrual period
The most common way to calculate your estimated due date (EDD) before an ultrasound is by using the first day of your last menstrual period. However, there are alternative methods depending on how you conceived and the information you have about your pregnancy.
To use this method, you'll need to know the date of the first day of your last period and the typical length of your menstrual cycle.
A normal pregnancy lasts an average of 280 days (40 weeks) from the first day of your last menstrual period.
Calculate EDD from conception
If you have an idea of when conception occurred, you can use that date to estimate your estimated due date (EDD). By adding 266 days to the date of conception, you’ll get an approximate EDD.
Conception always occurs within 24 hours of ovulation, as the egg can only survive for that long. However, sperm can live in the body for up to 6 days after intercourse.
Therefore, conception may not always align with the day of intercourse. For instance, if ovulation happens a few days after intercourse, conception could occur later.
Calculate EDD for IVF
If you became pregnant through IVF, you can calculate your estimated due date (EDD) using the date the embryo was transferred. Enter the date of the transfer along with the age of the embryo at that time.
The average length of a pregnancy from the embryo transfer date is approximately 266 days, minus the age of the embryo. For more accurate information and personalized advice, always consult your doctor overseeing your IVF treatment.
Calculate EDD from ultrasound
If you've had an ultrasound and received an estimated gestational age, you can use this information along with the date of the ultrasound.
Based on the estimated age of the fetus on the ultrasound date, we can help you calculate an estimated due date.