Pregnancy Due Date Calculator — Find Your Baby’s Due Date in Months, Weeks or Days

In simple words, our Enhanced Pregnancy calculator or Due Date Calculator solves the #1 pregnancy question: “When am I due?” – Covers Due Date by Conception, LMP, IVF and Ultrasound

[pregnancy_due_date_calculator]

Curious to Know Your Estimated Due Date?

When is your baby due? Use this pregnancy calculator to find your estimated due date based on the date of your last menstrual period, conception date, IVF three-day or five-day transfer date, or date of your last ultrasound. Enter either of these dates and the Due Date Calculator will provide a reliable estimate of your due date. You can estimate your due date in weeks, months, and trimesters timeline in your pregnancy.

Use our Pregnancy week Calculator by due date to track your pregnancy in months, weeks or days. This pregnancy month calculator or by-week calculator will tell you how many months or weeks am I pregnant from my last period. Our week to week pregnancy Calculator or pregnancy calculator month by month will calculate how many weeks or month you are pregnant. Whether you calculate Pregnancy week Calculator by LMP or use other method like Conception Date Calculator you will know when you’re expected to give birth.

How do I calculate my due date?

Your due date is calculated from the first day of your last menstrual period (LMP), not the day you conceived. So try to remember the day your last period started and add 40 weeks to that.

You can also calculate your due date with the following formula:

• Subtract three months from the first day of your last menstrual period
• Add seven days
• Add one year

For example, if the first day of your last menstrual period was June 2, 2025, subtract three months to get March 2, 2025. Add seven days and you’ll get March 9, 2025. Finally, add one year to find your estimated due date of March 9, 2026.

Why is pregnancy calculated from your last period?

The pregnancy clock starts even before sperm meets egg (and, actually, before your ovary even dropped the fated egg that made your baby). Using your last period is simply a more reliable benchmark to date a pregnancy from.

Even if you’re a master at tracking your cervical mucus and are sure about the day you ovulated — as well as the day(s) you had sex — you probably can’t pinpoint the exact moment of conception.

That’s because there’s a bigger window than you might think: Sperm can hang out and wait for an egg to fertilize for three to five days after they’ve arrived, and an egg can be fertilized for up to 24 hours after it’s been released.

“If someone knows their date of conception or date of ovulation, that could be used to narrow their specific due date, but as a general method, the first day of the last menstrual period is the standard for initially marking and communicating the estimated due date,” says Dr. Smith.

That’s also good news, since it means you’ll already have clocked four weeks of pregnancy by the time you miss your period.

Due Date calculator by weeks

Want to predict your baby’s delivery date using our Pregnancy weeks Calculator? It is typical for a pregnancy to last between 37 and 42 weeks. A pregnancy lasting beyond 42 weeks is considered post-term, which means the pregnancy is past its due date.

Assuming that you’re pregnant for 40 weeks and you have an average, regular cycle of 28 days:

• If you conceived in January, your baby may be due in October 
• If you conceived in February, your baby may be due in November 
• If you conceived in March, your baby may be due in December
• If you conceived in April, your baby may be due in January
• If you conceived in May, your baby may be due in February
• If you conceived in June, your baby may be due in March
• If you conceived in July, your baby may be due in April
• If you conceived in August, your baby may be due in May
• If you conceived in September, your baby may be due in June
• If you conceived in October, your baby may be due in July
• If you conceived in November, your baby may be due in August 
• If you conceived in December, your baby may be due in September 

Our due date calculator week-by-week will show Weekly Development for all 40 weeks. A complete week-by-week timeline will guide you through your pregnancy journey so you can keep track of your pregnancy from conception to delivery from week 1 to week 40. You will find all information related to that specific week and links that lead to detailed in-depth content.

Pregnancy month calculator by-week

To use our online pregnancy month calculator to see how many months you are pregnant, first find your estimated due date by adding 40 weeks to the first day of your last menstrual period. Our Pregnancy tracker then convert weeks to months using a general guideline like Month 1: Weeks 1-6, Month 2: Weeks 7-11, and so on. However, healthcare providers primarily use weeks for tracking due to the varying length of months and the fact that pregnancy is measured from the last menstrual period, not conception.

Pregnancy Weeks vs. Pregnancy Months

There are about 40 weeks in a full-term pregnancy. If you assume that a month is exactly four weeks long, that makes 10 months of pregnancy. The problem with this calculation is that it assumes that each month lasts 28 days—but most of our calendar months last 30 or 31 days.

To confuse matters even more, gestational age is calculated based on your last menstrual period (LMP) instead of your conception date. By the time you receive a positive pregnancy test, you’re usually about 4 weeks pregnant.

The truth is that a full-term pregnancy lasts between nine and 10 months. To establish clarity about your stage of pregnancy and estimated due date, your practitioner will track your pregnancy in weeks rather than months.

You can estimate your due date with our EDD Calculator or online calculator, like the one above.

How many weeks are in a trimester?

There are 13 or 14 weeks per trimester. While you might explain your pregnancy in weeks or months, many expectant parents also describe their pregnancy in trimesters.

How many trimesters are in a pregnancy?

There are three trimesters in a pregnancy, according to the American College of Obstetricians and Gynecologists The first trimester, which lasts from weeks 1 to 13; the second trimester, which lasts from week 14 to week 27; and the third trimester, which lasts from week 28 to week 40 (and up).

Pregnancy Trimesters by Week

Here’s a simple breakdown of approximately how the weeks, months, and trimesters are counted in pregnancy:

First Trimester
The first trimester usually includes weeks 1 through 13, or months 1 to 3. This is considered a short trimester because many people don’t know they’re expecting during the early weeks.

Second Trimester
The second trimester usually includes weeks 14 through 27, or months 4 to 6. Many parents consider this to be the easiest and most comfortable trimester.

Third Trimester
Your third trimester may include weeks 28 to 40, or months 7 to 9. But many people go into labor before week 40, and some may stay pregnant a week or two longer.

How do I know what week I am currently in my pregnancy?

Suppose your doctor says you’re 15 weeks pregnant, but you’re also hearing that you’re in week 16. Which is right? The short answer: both.

It turns out how many weeks into pregnancy you are is a little different than how many weeks pregnant you are. If you’re in week 16, you’re actually 15 weeks and some days pregnant. Fifteen full weeks have gone by, but not 16 weeks, so people say that you’re both 15 weeks pregnant and in week 16 of pregnancy.

Not convinced? Look at it this way: When you turned 1 year old, you had lived through your first year and were starting on your second. In other words, on your first birthday, you were in day one of your second year.

But no one said you were 2 years old until you’d finished that second year and had begun your third.

The same rules apply when talking about your weeks of pregnancy: You are x weeks pregnant, but in your x+1 week of pregnancy.

Counting Pregnancy Months

Understanding your pregnancy in weeks, months, and trimesters can be confusing enough. But you’ll also be faced with plenty of pregnancy questions from others. When someone asks: how far along are you? It’s usually easiest to reply in months.

Here are a few different ways to break down your pregnancy month.

Pregnancy by month: emphasis on first trimester

This monthly breakdown assumes that early pregnancy is very important. Since many people don’t know they’re pregnant during the first few weeks, month one is extended to six weeks.

Month 1: Week 1 through week 6
Month 2: Week 7 through week 11
Month 3: Week 12 through week 16
Month 4: Week 17 through week 20
Month 5: Week 21 through week 24
Month 6: Week 25 through week 28
Month 7: Week 29 through week 32
Month 8: Week 33 through week 36
Month 9: Week 37+

Pregnancy by month: emphasis on third trimester

This weekly pregnancy breakdown includes the last normal menstrual cycle, and it considers that some people have their babies earlier than forty weeks.

Month 1: Week 1 through week 4
Month 2: Week 5 through week 8
Month 3: Week 9 through week 12
Month 4: Week 13 through week 16
Month 5: Week 17 through week 20
Month 6: Week 21 through week 24
Month 7: Week 25 through week 28
Month 8: Week 29 through week 32
Month 9: Week 33+

Pregnancy by month: emphasis on calendar dates

This breakdown takes the date of your last menstrual period, and it uses that date in subsequent months. For example:

If the date of your last menstrual period was April 17:

Month 1: April 17 through May 16
Month 2: May 17 through June 16
Month 3: June 17 through July 16
Month 4: July 17 through August 16
Month 5: August 17 through September 16
Month 6: September 17 through October 16
Month 7: October 17 through November 16
Month 8: November 17 through December 16
Month 9: December 17+

Why You Should Rely on our Accurate due date calculators

Here’s why you should confidently rely on our Pregnancy tracker, developed by CuteNewborns, for a medically sound estimate.

1. Built on Gold-Standard Medical Guidelines

Our calculator isn’t based on a generic formula. It’s engineered using the latest evidence-based guidelines from the world’s leading obstetric authorities:

• ACOG (The American College of Obstetricians and Gynecologists): We use the ACOG-modified Naegele’s rule, which is the standard of care in the United States.
• ASRM/ESHRE (American Society for Reproductive Medicine/European Society of Human Reproduction and Embryology): For IVF pregnancies, we follow their precise consensus guidelines for dating, offering the highest possible accuracy.
• INTERGROWTH-21st Project: This groundbreaking international research provides the most accurate formulas for dating a pregnancy based on early ultrasound measurements, which we have integrated into our tool.

This means the calculations you get from us are the same type of calculations your healthcare provider uses.

2. It Adapts to Your Unique Pregnancy Journey

Every woman and every pregnancy is unique. A one-size-fits-all calculation doesn’t work. Our calculator accounts for this with multiple, sophisticated input methods:

• Last Menstrual Period (LMP) with Precision: We don’t just add 280 days. You can input your actual cycle length and luteal phase length for a personalized, more accurate due date.
• Due date Calculator from conception/Ovulation Date: Use our pregnancy due date calculator based on conception if you’ve been tracking your cycle with ovulation tests or basal body temperature. You can get a highly accurate due date based on this information.
• Ultrasound Dating: Our pregnancy due date calculator by ultrasound truly excels. You can input specific measurements from your early ultrasound (Crown-Rump Length, BPD, HC, AC, FL), and our tool uses clinically-validated formulas (Robinson & Fleming, Hadlock, INTERGROWTH-21st) to calculate your EDD.
• IVF Embryo Transfer: We provide specific options for Day 3, Day 5, and Day 6 embryo transfers, following strict ASRM/ESHRE protocols for the most accurate dating possible.

3. We Are Transparent About Confidence and Accuracy

A key sign of a medically reliable tool is that it acknowledges the limits of its own accuracy. Our calculator doesn’t just spit out a date; it tells you how confident that estimate is.

• Confidence Indicators: Based on the method you use, we provide a confidence level (High, Moderate) and show the statistical range (± days).
• Clinical Notes: Each method includes helpful clinical notes explaining the factors that affect its accuracy (e.g., “LMP dating assumes ovulation on day 14…”).
• ACOG Redating Thresholds: Our underlying logic follows ACOG’s rules for when an ultrasound date should take precedence over an LMP date, ensuring the result is clinically plausible.

4. More Than Just a Date: Your Pregnancy Timeline

We believe in empowering you with knowledge. Our results page provides a comprehensive overview of your pregnancy:

• A visual timeline showing your progress through each trimester.
• Key details about your current week of pregnancy.
• Fun, personalized facts about your due date.
• A clear explanation of the methodology used to calculate your date.

The Bottom Line: Trust, But Verify

We are confident that our calculator provides one of the most medically accurate and reliable estimates you can get outside of a doctor’s office. It is an excellent tool for satisfying your curiosity, preparing for your first appointment, and understanding how your due date is determined.

However, we always include this crucial disclaimer: Your healthcare provider will determine your final due date. They will consider your full medical history, conduct a physical exam, and review ultrasounds. Use our calculator to get a well-informed, evidence-based estimate, and then use that knowledge to have a more productive conversation with your doctor.

What is an estimated due date during pregnancy?

Your due date is a calculation of when you’re expected to give birth. An Estimated Due Date (EDD), also known as the “expected date of delivery,” is the calculated date when a pregnant person is expected to give birth. It is important for you to know as you prepare to welcome your baby.

Your due date is just an estimate, not a deadline for your baby to arrive! Only about 5% of moms give birth that day. You’re just as likely to go into labor within the two weeks before or after.

Our pregnancy Due Date Calculator (or estimated Due Date Calculator) can help you calculate your due date. By entering in the date of your last period, the date you conceived if you know it, the timing of your IVF transfer, or your first ultrasound date, the Pregnancy calculator will estimate your due date.

How Does the Pregnancy Due Date Calculator Work?

To determine “How is my due date calculated”, you give specific inputs like your Last Menstrual Period (LMP), Conception Date, IVF or any early ultrasound.

If you happen to know the date you conceived, you can count 38 weeks from that day to find your due date. (Human gestation takes about 38 weeks.)

To use our tool, simply enter one of these key dates into the input fields. Based on the data you provide, the calculator will process the information and estimate your due date.

Here’s how each calculation works:

• LMP: If you enter the first day of your last menstrual period, the tool calculates your due date assuming a 28-day cycle.
• Conception Date: If you know when conception occurred, the calculator will use that date for a more accurate estimate.

But very few expectant moms know exactly when they conceived. Even if you only had sex once during your fertile period, you wouldn’t conceive on that day unless you happen to be ovulating.

Sperm can live for up to five days inside your fallopian tubes. Meaning it could be up to five days after you have sex that you release an egg (ovulate) and it gets fertilized by a waiting sperm. That’s the day you conceive.

So without knowing the day of conception, how does anyone determine a due date?

When estimating your due date, several methods can be used. The method you choose depends on the available information and your specific circumstances. Whether it’s based on your last period, conception date, IVF transfer, or an early ultrasound, your healthcare provider will use the best method to estimate when your little one will arrive. Here are the primary and reliable ways to calculate your pregnancy due date.

Method 1: First day of last period or Last Menstrual Period (LMP)

The most common way to calculate your pregnancy due date is by counting 40 weeks (280 days) from the first day of your last menstrual period (LMP). That’s how most healthcare providers do it and that’s how our EDD calculator by LMP works. Pregnancy month calculator by LMP will tell you your months into pregnancy.

If your menstrual cycle length is the average length (28-day cycle), your period probably started about two weeks before you conceived. This explains why pregnancies are said to last 40 weeks instead of 38 weeks.

This method doesn’t take into account how long your cycle actually is or when you think you might have conceived. But generally speaking, women typically ovulate about two weeks or 14 days after their menstrual cycle starts. And women are more likely to know when their last period started than the day they ovulated.

If you know the first day of your last menstrual period, you can use our Due Date Calculator and select options Due Date by LMP to predict your estimated due date. It’s simple and widely used but may not be as accurate for women with irregular cycles or those who don’t ovulate on day 14.

To calculate your baby due date calculator by lmp:

• Start with the first day of your last period.
• Add 280 days (or 9 months and 7 days).

While this method is effective for many women, it may not be suitable for those with cycle lengths longer or shorter than 28 days. For instance, women with longer cycles may ovulate later, which means their due date will need adjustment.

Method 2: Due Date calculator by Conception Date

How to calculate due date based on conception using our pregnancy week or month calculator? If you have been tracking ovulation or using ovulation test strips or predictor Kit for recognizing your ovulation window, the Conception Date Method is a more accurate way to estimate your due date.

This method adds 266 days (or approximately 38 weeks) to the date of conception. It is most accurate for women who have tracked ovulation closely or for those who know the exact date of conception (often through fertility treatments like IUI). Just choose that calculation method from the pulldown above and put in your date.

This method is particularly useful for women with irregular cycles or who have tracked ovulation through various methods like basal body temperature or ovulation predictor kits. Remember, you don’t necessarily conceive on the day you have sex.

Method 3: Due Date Calculator IVF Transfer Date Method

For women who conceive through In Vitro Fertilization (IVF), the IVF Transfer Date method is highly precise. This method uses the exact date of the embryo transfer to calculate the due date, as the transfer date is known with certainty.

• Day-three embryo transfer: If your transfer was on day three, your due date is calculated by adding 263 days from the transfer date.
• Day-five embryo transfer: If your transfer date was on day five, your due date is calculated by adding 261 days.

IVF offers a very accurate pregnancy calculation because the exact date of conception (embryo transfer) is known. This eliminates any uncertainties associated with menstrual cycles or ovulation dates. Simply select “IVF” from our Accurate Due Date Calculator or pregnancy tracker method choices.

Method 4: Due Date Calculator by Ultrasound Scan

An Ultrasound scan is a reliable method for determining the due date, especially if you can’t pinpoint the date of conception or your last menstrual period. Early ultrasounds, typically taken in the first trimester, are most accurate for estimating the due date as they measure the size of the fetus, especially in the first 12 weeks.

In early pregnancy, ultrasound measurements of the fetus can often give a more accurate due date than LMP, especially for women with irregular cycles, those unsure of ovulation timing, or those who have longer or shorter cycles. If your due date is uncertain or if you have irregular periods, Just choose “ultrasound” from our Due Date tool to find out your big day.

Just be aware, however, that not all women get an early ultrasound. Some practitioners perform them routinely, but others only recommend one if your periods are irregular, you’re 35 or older, you have a history of miscarriages or pregnancy complications, or the due date can’t be determined based on your physical exam and LMP.

Other clues can help your health care provider figure out how far along you are and better pinpoint your due date at your prenatal check-ups.

Pregnancy milestones such as the first time the baby’s heartbeat is detected (around week 9 or 10, though it can vary) and when you first feel fetal movement (on average between 18 and 22 weeks, but it can be earlier or later), can give clues as to whether your due date is accurate.

Your fundal height, which is the measurement from your pubic bone to the top of your uterus, is checked by your practitioner at each prenatal visit and helps confirm your due date.

The size of your uterus, which will be noted when your initial internal pregnancy exam is performed, can also be a factor in pinpointing the EDD.

How to calculate pregnancy week with due date?

Use our pregnancy week calculator to find your estimated due date (EDD), enter the date of the first day of your last period, and select ‘show your estimated due date’. Pregnancy normally lasts from 37 weeks to 42 weeks from the first day of your last period.

How to calculate LMP?

To calculate your Last Menstrual Period (LMP), you add 280 days (or 40 weeks) to the first day of your last menstrual period, which is the most common method for estimating a due date in a pregnancy. An alternative method, known as Naegele’s Rule, involves counting back three months from your LMP, then adding seven days and one year.

When did I conceive by due date?

Wondering how is my due date calculated from Conception Date? If you have been using an ovulation predictor kit or tracking your ovulation you may be able calculate your due date based on the precise date of conception. In order to do this simply count 266 days, or 38 weeks, from the conception date to find your estimated due date.

Can I plan my due date?

You can try to time when you conceive in order to “plan” your due date. But even if you’re one of the lucky ones who’s able to get pregnant when she really wants to, just remember that you probably won’t be able to map out exactly when you’ll give birth to the day (or even the week or month!).

Still, you can try Ovulation Calculator, which uses the date of your last menstrual period and your typical cycle length to discover the days you’re most likely to be fertile and increase your chances of conceiving.

How Accurate is My Pregnancy Due Date?

Several factors influence the accuracy of your due date, including cycle length, the method used, and any individual differences, such as IVF procedures or the timing of your ultrasound. For instance, the Last Menstrual Period (LMP) method assumes a 28-day cycle, which may not apply to women with shorter or longer cycles.

Women with irregular cycles or those who don’t ovulate on day 14 may experience discrepancies between their calculated and actual due date. On the other hand, IVF and ultrasound methods tend to offer more precise due date estimates, as these are based on specific, trackable events like embryo transfer dates or early fetal measurements.

In general, while due dates are not guaranteed, they are still reliable and can help guide your preparations. Most pregnancies are delivered within a week or two before or after the estimated due date, with only about 5% of babies actually being born on their exact due date.

Can My Due Date Change?

Yes, due dates can change during pregnancy. For example, an ultrasound may adjust a due date because of the increased accuracy of using fetal measurements or if your cycle is longer or shorter than 28 days this can lead to a due date adjustment as well.

While a Due Date Calculation provides a helpful general estimate, the actual due date may shift as new information becomes available or through the natural variability in the growth of each baby during pregnancy. Your healthcare provider will measure your baby during that ultrasound exam to figure out how far along your baby is and then provide you with a new due date.

It could also be because your fundal height is abnormal, or your levels of alpha-fetoprotein (AFP), a protein made by the baby, are outside the usual range. Talk to your practitioner if you have any questions or concerns.

What If I Already Know My Due Date?

Even if you already know your due date, Our Pregnancy Due Date Calculator can still be incredibly helpful. By entering your known due date the Pregnancy Due Date Calculator can provide you with a detailed pregnancy timeline, outlining key milestones and detailed information for that week. You’ll also find out what your baby’s sign and birthstone will probably be and a few famous people who were born on your due date.

How likely am I to give birth on my due date?

Of course, a due date calculation is always approximate, whether it’s from our pregnancy calculator or from your doctor or midwife. Only 1 in 20 women delivers on her due date. You’re just as likely to go into labor any day during the two weeks before or after.

How soon can I take a pregnancy test?

You may be wondering when you can take a pregnancy test. To ensure you get the most accurate reading, it’s best to wait a few days after your missed period to take a pregnancy test.

At-home urine tests measure the amount of hCG (human chorionic gonadotropin) present in your body. If you take a pregnancy test before you miss your period, you may not get an accurate result, despite what some tests advertise.

If you’re getting a blood test in your provider’s office, you may get results sooner. These tests also measure the amount of hCG in your bloodstream, but they’re more sensitive than at-home urine tests. Blood tests may be able to detect pregnancy six to eight days after ovulation.

The significance of a due date for prenatal care

According to Dr. Twogood, understanding your due date can help you and your doctor plan the phases of your pregnancy, expected milestones, and when to arrange medical checkups. “Knowing your due date and therefore the gestational age of your pregnancy helps guide optimal prenatal care,” she says.

For example, she explains, the recommended time to screen for gestational diabetes is between 24 and 28 weeks of pregnancy. If the test is done before 24 weeks or after 28 weeks, the results might not be as accurate for diagnosing or ruling out gestational diabetes.

Knowing your due date and gestational age also helps you and your doctor set expectations when a pregnancy is high risk, she adds. “Especially in the case of preterm birth, to use an extreme example, knowing if a baby will be 24 weeks or 28 weeks at the time of birth is a big difference!”

How many weeks is pregnancy?

The majority of pregnancies last between 37 and 42 weeks. It’s likely that you’ll give birth a little before or after 40 weeks, but this estimate helps healthcare providers time your prenatal care. Your due date may be adjusted if you have an ultrasound or testing that shows your pregnancy is further along than you thought.

How can I know how far along I am?

When you calculate your due date with our Due Date Calculator tool, you’ll also find out how many weeks pregnant you are.

Will my due date change?

That depends! Your provider may change your due date if an ultrasound shows your baby is significantly bigger or smaller than expected based on your last menstrual period. Usually you can expect your due date to stay the same, but remember it’s just an estimate.

What is EDC in pregnancy?

The accurate determination of a patient’s “due” date, referred to by doctors and midwives as the EDC (Estimated Date of Confinement) or EDD (Estimated Date of Delivery).

Is pregnancy nine or 10 months long?

Your 40 weeks of pregnancy are counted as nine months (even though pregnancy is a just little bit longer than nine months). But wait … there are four weeks in a month, which would make 40 weeks 10 months. Right? Not exactly.

Four weeks is 28 days, but months (with the exception of February, of course) have 30 or 31 days, making each month about 4.3 weeks long.

“It can be confusing, since we talk about trimesters, but the length of pregnancy isn’t evenly divisible by three,” says Shannon Smith, M.D., an OB/GYN at Brigham Faulkner OB/GYN Associates in Boston, Massachusetts.

My pregnancy test is positive, what should I do next?
If you receive a positive pregnancy test result, the next step is to schedule an appointment with your healthcare provider. They will confirm the pregnancy, discuss prenatal care options and provide guidance on maintaining a healthy pregnancy.