Just found out you’re pregnant? You’re probably feeling a mix of excitement, nerves and about a hundred questions. One of the first things on your mind is likely: when is my baby due?
Our Pregnancy Due Date Calculator helps you work out your estimated due date based on the first day of your last period and the length of your cycle. It’s quick and easy to use, and prepares you for things like booking your first scan, thinking about your trimesters, or simply sharing the news with loved ones.
Babies rarely arrive right on cue, but knowing your estimated due date is a helpful anchor for everything that comes next.
This is an estimated date of when your baby is due. Babies rarely keep to an exact timetable, so your full-term pregnancy can be anywhere from 37 and 42 weeks.
Medically reviewed by Hannah Dahlen, Midwife and Professor of Midwidery The most common way to calculate your due date is by using the first day of your last menstrual period (LMP) and your average cycle length.
Here’s how the calculator works:
This method is reliable for people with regular cycles. If you’ve been tracking your cycle with an app or journal, use those records to be as accurate as possible.
If your cycle is irregular or you’re unsure of your dates, don’t stress. You can still use this as a guide for now. Your healthcare provider may adjust your due date based on scans or other information later on.
And if you’re not sure of your average cycle length, leave it at 28 days. This is the standard used in most due date calculations.
If your cycle isn’t regular, or you know the exact conception date, there are a few ways to estimate when baby will arrive.
These include:
Your estimated due date (EDD) is exactly that – an estimate. It’s based on available information, like your cycle dates or scans, and gives a rough idea of when your baby might arrive.
Full-term pregnancies typically last between 37 and 42 weeks. Only a small number of babies are born on their exact due date, so think of it as a guide rather than a deadline.
It helps you plan, book appointments and track your baby’s development. But there’s always a little flexibility, babies tend to make their entrance when they’re ready.
How accurate is the due date calculator, and what affects it?
The calculator gives you a close estimate, but factors like irregular cycles, ovulation timing or scan results may lead to changes later on. Your doctor may update your due date based on early ultrasounds.
Does cycle length impact my due date?
Yes. Shorter or longer cycles shift your likely ovulation date. Adjusting for your actual cycle length makes the result more personalised, especially if you’re outside the 28-day average.
Can my due date change later in pregnancy?
It can. Your provider might adjust your due date after an early scan. Ultrasounds in the first trimester are usually more accurate than LMP-based estimates alone.
