Pregnancy Due Date Calculator

Find Out Your Baby’s Estimated Date of Arrival with Our Pregnancy Due Date Calculator!

Wondering when your little one might make their entrance into the world? This straightforward due date calculator provides a quick, personalised estimate based on the date of your last period or conception. It’s a simple way to understand. Start planning with a touch more peace of mind.

Choose Your Calculation Method

Give our Due Date Calculator a try below to find your estimated due date in just a few clicks.

How to Use the Due Date Calculator

A positive pregnancy test can trigger a wave of emotions and questions. One of the first may be: “When is my due date?”

This easy-to-use due date calculator helps you estimate how many weeks pregnant you are in just a few steps:

1. Start by noting the first day of your last period or, if you know it, the exact date of conception.
2. Enter that date into the calculator.
3. Click “Calculate your due date” to get your estimated result.

That’s it! Please note that every pregnancy is unique, and this tool provides an estimated due date, not a guaranteed one.

Which Calculation Method Should I Use?

Your due date can be estimated in a few different ways:

1. From the first day of your last period
2. The conception date
3. An IVF transfer date
4. An early ultrasound.

With this due date calculator, you can estimate your due date based on either your last period or the day you conceived.

Using the first day of your last period is the most common method. While pregnancy typically lasts about 40 weeks, the count starts from the first day of your menstrual cycle, not the day you conceived. That’s why by the time you get a positive test, you might already be several weeks along.

If you're not meticulously tracking ovulation, figuring out how to calculate pregnancy weeks can be quite challenging. That's where a pregnancy week calculator comes in handy. Just input the date of your last period and your cycle length. The tool will then adjust based on whether your cycle is shorter, longer, or average.

If you know the exact date of conception, the calculator can also work out your due date by counting 266 days from that day. In any case, it's an easy way to gain a better understanding of your pregnancy journey.

What About IVF?

If you became pregnant through in-vitro fertilisation (IVF), you can work out your estimated due date from the date of your embryo transfer, which is when the fertilised egg was successfully implanted. Since the timing can differ depending on whether the transfer was fresh or frozen, your GP is the best person to provide the most accurate estimate.

What is an Estimated Due Date?

Knowing your due date is essential for understanding your pregnancy timeline. Typically, it’s calculated as 280 days from the start of your last period. This helps you keep track of your pregnancy's progress and anticipate key milestones.

It’s a useful tool for determining how many weeks along you are at any point.

Can My Due Date Change?

Your due date might shift as your pregnancy moves along. Even with the best estimates, only around 5% of babies arrive on their expected date. Factors like irregular cycles or relying solely on your last period without an early scan can impact the accuracy.

Your doctor might adjust your due date based on later scans or new information.

Can I plan my due date?

You can certainly plan when you would most like to conceive and become pregnant—that’s an important aspect of family planning. Using our Pregnancy Due Date Calculator, you can enter various conception date options and receive estimated due dates. But do keep in mind that you may not get pregnant exactly when you want to and that it’s best to give yourself a range of dates.

You can also use the date of your last period and your typical cycle length to determine when you're most likely to be fertile. This information can help boost your chances of conceiving within a certain time frame, getting you closer to your ideal due date.

Now That I Have My Estimated Due Date, What's Next?

Having a clear due date helps you plan for your baby's arrival. Start by booking a prenatal check-up. Your doctor will confirm the pregnancy and monitor important developments, such as the baby's heartbeat and growth through scans.

At your first visit, they may estimate your gestational age by checking your uterine size or ordering an early ultrasound scan. Depending on what they observe, your due date may be adjusted later.

In the meantime, you can start following your milestones with tools like the Pregnancy Calendar  - a helpful way to stay informed, organised, and connected to your journey week-by-week.

How to calculate gestational age?

The gestational age refers to the age of a foetus or newborn. It starts on the first day of the mother’s last menstrual period and is often measured in weeks. The gestational age is used to estimate the developmental stage of the foetus and predict its expected due date. 

FAQ

How does a due date calculator work?

It estimates your due date based on the first day of your last menstrual period or your conception date, following a standard 280-day pregnancy model.

Is it better to calculate the due date from conception or the last period?

Both methods are commonly used. Since the exact date of conception is often unknown, most providers use the first day of your last period to estimate how many weeks pregnant you are.

Explore More Tools/Relevant Content

Now that you’ve estimated your due date, you might be thinking ahead to other exciting milestones. These topics can help you plan for what’s next:

• Determine your baby's sex. Learn what determines your baby's sex and when and how gender can be accurately identified medically, including your mid-pregnancy ultrasound at around week 20. 
• Old wives’ tales for predicting gender. Still waiting for that ultrasound? Explore some fun (though unscientific) gender-predicting traditions while you wait.
• Gender reveal ideas to inspire you. Whether you’re planning something big or keeping it intimate, check out creative ways to share your baby’s gender with loved ones.

And if you haven’t already, consider downloading the Pampers Club App. It’s an easy way to unlock exclusive offers and savings on Pampers products as you prepare for the arrival of your little one.

How We Wrote This Page
The information in this article is based on the expert advice found in trusted medical and government sources, such as the National Health Service (NHS). You can find a full list of sources used for this article below. The content on this page should not replace professional medical advice. Always consult medical professionals for full diagnosis and treatment.