What month will my baby be born? Try our due date calculator
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There are a few different ways to find out.
Jose Luis Pelaez/Getty Images
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Pretty much every mama out there has found themselves searching the internet for a due date calculator. Whether you are trying to conceive with specific timing in mind, or are already pregnant and curious to know when your little bundle will arrive, thinking about due dates is exciting—and gives you a thrilling countdown.
When trying to calculate your due date, your medical team will often start with your last menstrual period, or LMP (the first day of your last period, to be exact). From there, we can estimate the due date based on a simple mathematical equation (more on that below).
Related: What does a faint line on a pregnancy test mean?
But what if you don’t remember the first day of your last period? Or what if you are someone who doesn’t get regular periods? Don’t worry.
As I share in “The Motherly Guide to Becoming Mama” it’s common for women not to know when their LMP was. If that’s the case, your doctor or midwife will likely recommend what’s known as a dating ultrasound to help determine how far along you are.
Let’s discuss what due dates are, and most importantly, how to determine when your due date is. Try our pregnancy month calculator below!
What is a due date?
Due dates can encompass a range of terminology, all referring to the same thing. You might hear:
- Estimated date of delivery (EDD)
- Estimated date of childbirth (EDC)
- Estimated date of confinement (EDC) (Wait, what? Back in the day, women were confined to a bed or hospital when they gave birth, hence the word confinement.)
- Guess day
Whatever phrasing you use, your due date is the day that birth providers estimate your baby will be born.
Related: The new mama’s guide to pregnancy symptoms
Wondering how to find your due date? Enter the first day of your last period, length of average menstrual cycle and average luteal phase length below for a peek at a possible due date. Or try our simple formula below.
This due date calculator is for informational purposes only. It does not constitute medical advice. For your most accurate due date, talk to your practitioner.
How long is pregnancy?
Pregnancies last approximately 280 days, which is 40 weeks, or about 10 months—not nine like we traditionally hear. Your pregnancy is considered full-term after 37 weeks, 0 days. Delivery prior to 37 weeks is considered preterm.
- At 37 weeks to 38 weeks, 6 days, the pregnancy is considered early-term (technically full-term, but on the early side of it)
- At 39 weeks to 40 weeks, 6 days, the pregnancy is considered full-term
- At 41 weeks, the pregnancy is considered late-term
- At 42 weeks, the pregnancy is considered post-term
When is my due date?
There are a few ways to calculate your due date. Your due date is based on the first day of your last menstrual period (LMP). Here is the formula:
- Write down the first day of your last LMP
- Subtract three months
- Add seven days
Let’s take a look at an example. If you get pregnant in June what month are you due? Say your LMP was on June 10:
- Subtracting three months from June brings you to March.
- Adding seven days to 10 gives you 17.
- Your due date will be March 17.
Here’s another example. If you get pregnant in February what month are you due? Say your LMP was on February 21:
- Subtracting three months from February brings you to November.
- Adding seven days to 21 gives you 28.
- Your due date will be November 28.
You can also use a due date calculator, which can help if you know the day of intercourse, insemination or embryo transfer, or try our handy graphic below.
Related: Am I ready for a baby?
Try our due date calculator
For all those planner mamas-to-be: Our pregnancy month calculator can help you figure out the month your baby is due to be born based on your conception month. If you want to get pregnant in January, for example, you’re likely looking at an October baby!
Related: September is by far the most popular birthday month—and here’s why
Using ultrasounds to determine your due date
For a variety of reasons, a lot of women don’t know when their last period was (so don’t worry if you’re not sure, mama). A history of irregular periods, medications and plain ol’ forgetting are all normal reasons to be unsure.
A transvaginal ultrasound (where a lubricated ultrasound wand is inserted into the vagina) can help pinpoint your estimated due date, especially when done in the first trimester. The ultrasound technician will measure the size of the embryo and use the information gathered to determine your due date.
Surprisingly, as your pregnancy progresses, it becomes harder to calculate the gestational age and size of the fetus with an ultrasound (the bigger they get, the more inaccurate the measurements are).
Related: 9 essential questions to ask during your first prenatal visit
How accurate are baby due dates?
In short, due dates are not very accurate. In fact, only about 4% of women will give birth on their due date. Note that baby due dates are not expiration dates! Most first-time moms will give birth 3 to 5 days past their due date, and a great many go longer than that still.
Related: Do second babies come faster?
Going past your due date can be frustrating. Your provider will discuss all of your options, like waiting for labor to start on its own versus scheduling an induction with you. (Psst: If that’s you, here’s how to give yourself grace when you go past your due date.)
Ultimately, due dates are really exciting to think about—but my recommendation is to try to think of them as an approximation. Instead of saying, “I’m due on May 15th,” maybe try, “I’m due sometime in May!”
Your baby will come, and when they do, it will be the most perfect date of all: Your baby’s birthday!
Frequently asked questions about pregnancy due dates
What month do you have to get pregnant to have a baby in July?
Dreaming of a July baby, mama? Aim to conceive in October. While Mother Nature has her own timeline, October conception could lead to those summer baby snuggles.
When would I be due if I got pregnant this month?
If you got a positive test this month, count forward 40 weeks from the first day of your last period. That’s your baby’s estimated due date. But remember, it’s just an estimate—your little one decides the actual day!
When am I due if I conceived in March?
Conceived in March? Your bundle of joy is likely to arrive in December. Picture your little one’s first holiday season wrapped up like the best present ever.
What month do you have to conceive to have an August baby?
To plan for an August arrival, you’d typically look at conceiving in November. Yes, your little sunshine could be a summer baby!
When is your due date if you are pregnant in April?
If April showers brought you a little something extra, expect your bundle around January. A new year and a new life, how exciting!
Is the day I conceived the day I got pregnant?
Conception is the exact moment your egg meets sperm. But, we date your pregnancy from the first day of your last period for consistency, since pinpointing the exact moment of conception is tricky.
How do you know exactly when you conceived?
Knowing the exact day of conception can be tough unless you’re tracking ovulation or underwent assisted reproduction. But, symptoms, ultrasounds, and your last period can give good clues.
Do you count the month you conceived?
In the world of pregnancy tracking, the clock starts ticking from the first day of your last menstrual period, even though conception occurs about two weeks later. So yes, in a way, we count the month you conceived, but we start counting a couple of weeks before the magic moment.
A version of this post was originally published on June 26, 2018. It has been updated.
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