Pregnancy Due Date Calculator: When Am I Due?

How do I calculate my due date of pregnancy?

You can work out your due date by using your LMP (last menstrual period) as an indicator, although if you have irregular periods, you can use your first ultrasound as a dating scan.

The first day of your LMP marks the first day of your first week of pregnancy.

Then, 40 weeks from that date is baby’s due date (although babies don’t often arrive exactly on their due date)!

But to save you the hassle of adding 40 weeks to the date of your last period, we’ve put together our fast and accurate pregnancy due date calculator, so you can get your due date results in seconds.

It can help to know the length of your typical menstrual cycle (which is usually from 21-35 days) to get the most accurate result.

What is a due date in pregnancy?

The due date meaning is the date that baby is predicted to make their appearance ‒ the day you can hold them in your arms and look into their eyes.

Note we say “predicted” here ‒ after all, no due date is ever entirely accurate, even if you choose to schedule an elective c-section.

There’s a chance that baby could be early (a premature baby), late, or just a few days either side of your due date.

In fact, research has found that 60% of women give birth on or before their due date, but another 35% get going in the 41st week or 42nd week of pregnancy.

But knowing your due date can give you an idea of when baby will be here, so you know when to start sorting their nursery and picking out baby names.

If you’re wondering When am I due?, just use our quick and easy baby due date calculator.

What is “due date” in Spanish?

If you have Spanish family or are keen to practise your language skills, you may be intrigued to learn that “due date” in Spanish is “fecha de embarazo”, pronounced “fey-cha day em-bah-raht-zo”.

What are “due date” synonyms?

There are so many ways to talk about your pregnancy due date ‒ here are our favorite due date synonyms:

• Baby’s grand entrance
• Baby’s first appearance
• Estimated date of confinement (EDC) ‒ although this is a medical term
• Expected date
• Birth date
• Estimated due date (EDD)

How accurate are due date calculators?

Our pregnancy due date calculator is the most accurate way of predicting your baby’s due date.

But, as accurate as our baby due date calculators is, it’s not going to be 100% correct, as baby might decide to make an early appearance or be a couple of weeks late.

Can my pregnancy dates be wrong?

If you’re using a pregnancy due date calculator and you know the date of the first day of your period, no, it’s not possible for your pregnancy dates to be wrong.

However, you can also use an ultrasound to date your pregnancy, although these can sometimes be inaccurate.

This is especially true the later on in your pregnancy ‒ if, for example, you find out you’re pregnant after week 18 of pregnancy, there’s about a 2 week margin of error either side if you’re working out your due date from an ultrasound.

The further along in your pregnancy, the less accurate your due date calculation will be from an ultrasound.

Can my due date change?

Not often, but sometimes, yes, your due date can change, even if you’re using a due date calculator based on the date of your last period.

But at 42 weeks, you’ll be recommended for an induction of labor , so even if baby doesn’t make an appearance on their exact due date, you can be sure they’ll be here in just a couple of weeks at the latest.

Which EDD is more accurate?

Of course you want the most accurate pregnancy due date calculator around ‒ well, luckily, you’re in the right place!

There are two main ways of figuring out baby’s due date: by using a baby due date calculator (like this one) or by having your doctor figure out how old baby is from an ultrasound.

Of the two methods of working out your due date, a pregnancy due date calculator is the most accurate.

This is because ultrasounds require a certain skill and precision to read, and baby may be lying in a way that makes them look bigger or smaller than they actually are.

However, a pregnancy due date calculator uses the date of your last period to more accurately predict baby’s due date.

Is LMP accurate for due date?

Yes, your LMP ‒ or last menstrual period ‒ is the most accurate way of calculating your due date.

Although to get the best due date result, knowing how long your typical menstrual cycle is (usually from 21-35 days) can give you an even more accurate result.

What is the first day of last period?

So what is classed as the first day of your last period?

Well, it’s the first day you start your (roughly) monthly bleed ‒ spotting doesn’t count as a first day of your last period, it must be your normal full flow.

It can be hard to calculate your pregnancy due date if you don’t know the date of your last period, so tracking your menstrual cycle is recommended if you’re trying to conceive.

Why is due date calculated from LMP?

So just why is your last menstrual period so important in determining your due date?

Well, it comes down to ovulation.

Generally speaking, most people with regular periods ovulate about two weeks after the first day of their last period ‒ this is when you’re most likely to get pregnant, also known as your fertile window.

While it is possible to get pregnant outside of your fertile window, it’s very uncommon, so using the date of the first day of your last menstrual period is the most accurate way to calculate your due date.

Which EDD is more accurate LMP or ultrasound?

So in the battle of LMP and ultrasounds as a pregnancy due date calculator, the date of the first day of your last menstrual period reigns supreme as the most accurate of the two.

What should I do when I know my due date?

If you’ve just used our pregnancy due date calculator, you’ve marked it in your diary and you’ve started your due date countdown, what next?

Well, it’s totally up to you, mama!

But here are some suggestions of things to do at different points in your pregnancy:

• Buy baby’s first outfit.
• Announce your pregnancy.
• Look for a doula, midwife, OB/GYN, or pediatrician that works for you.
• Sign up for a birth or parenting class.
• Look into pregnancy diets and pregnancy-safe exercises to stay healthy.
• Plan your birth preferences.
• Ask about maternity leave, if you’re employed.
• Start researching the different baby essentials you’ll need (stroller, crib, bottles, burp cloths…)
• Pick out potential baby names.
• Plan your baby shower (or sprinkle, if you want something smaller).
• Join Peanut to find your Bump Buddies with baby due dates in the same month.

🤰 More on pregnancy from Peanut:

• I’m Pregnant, Now What? Your Pregnancy Checklist
• Your Pregnancy Week-by-Week Guide
• What To Do When You Find Out You're Pregnant
• 6 Things No One Tells You About Pregnancy
• Pregnancy Weeks to Months: Your Calculator
• What Will My Baby Look Like?
• Pregnancy Must-Haves: Top 10 Pregnancy Products by Peanut