Due Date Calculator: See Your Pregnancy Timeline & Trimesters

How to Use Our Due Date Calculator

This calculator provides several ways to estimate your due date, ensuring you get the most accurate result based on the information you have.

• 1. From Last Menstrual Period (LMP) – Most Common

  • First Day of Last Period: Select the date your last period began. This is day one of your cycle. Your 40-week pregnancy timeline officially starts from this day, even though conception occurs about two weeks later.

  • Average Cycle Length: Enter the number of days from the start of one period to the start of the next. The average is 28 days, but entering your specific cycle length helps create a more personalized and accurate estimate of your ovulation and due date.

• 2. From Conception Date

  • Date of Conception: If you tracked ovulation and know your conception date, enter it here. A pregnancy is 38 weeks from the date of conception.

• 3. From IVF Transfer Date

  • IVF Transfer Date: Select the date of your embryo transfer.

  • Embryo Type: Choose whether you had a 3-day embryo transfer or a 5-day blastocyst transfer.

• 4. From an Ultrasound

  • Date of Ultrasound: Enter the date of your scan.

  • Weeks & Days Pregnant at Scan: Input the gestational age (e.g., 8 weeks and 2 days) that the scan determined. This method is excellent for confirming or establishing a due date if you have irregular cycles.

Understanding Your Results

Your due date is more than a single day on the calendar; it’s the anchor for your entire pregnancy journey. Here is a breakdown of your personalized results.

• Your Estimated Due Date: This is the date your baby is projected to be born. It is calculated by adding 280 days (40 weeks) to the first day of your last menstrual period. It is important to remember this is an estimate. Most babies are born in the two weeks before or after this date.

• You Are Currently: This tells you precisely how far along you are today—Saturday, July 26, 2025—in weeks and days. This is your “gestational age,” the standard measurement used by doctors.

• Estimated Conception Date: Based on your inputs, this is the most likely date that conception (fertilization) occurred.

• Baby’s Astrological Sign & Birthstone: A fun look at the zodiac sign and birthstone associated with your baby’s estimated due date.

Your Personal Pregnancy Timeline

Your pregnancy is a series of amazing milestones. Here are the key dates in your journey based on your results:

Frequently Asked Questions

How accurate is a due date calculator?

A due date calculator provides a very good estimate, but it’s important to think of your due date as a “due week.” Only about 5% of babies are actually born on their exact due date. It is perfectly normal and healthy for a baby to be born anytime between 38 and 42 weeks of pregnancy. The calculator gives you a target to plan around, but be prepared for your baby to arrive on their own schedule.

Why did my doctor change my due date after an ultrasound?

This is very common and a good thing! An early ultrasound, especially one done in the first trimester (weeks 6-13), is the most accurate method for dating a pregnancy. During this time, all fetuses grow at a very predictable rate. A sonographer will measure the baby’s Crown-Rump Length (CRL), which can pinpoint the gestational age, often more accurately than an LMP calculation. If your doctor gives you a new date based on a scan, that is the more reliable date to use.

What if I have irregular periods or don’t know my last period date?

If your cycles are irregular, the “Last Menstrual Period” method can be inaccurate because it’s difficult to know when you ovulated. In this case, the best course of action is to see a healthcare provider for a dating ultrasound. If you have no idea when your last period was, a doctor will rely entirely on an ultrasound to establish your due date.

Can my due date be wrong?

Yes, an initial due date can be off, usually for a few key reasons:

• Misremembering the LMP: It’s easy to be a few days off on the start date of your last period.

• Irregular Ovulation: If you ovulated earlier or later than day 14 of your cycle, the standard calculation will be inaccurate.

• Typo in Calculation: A simple data entry error can change the date.

This is why the first-trimester ultrasound is so valuable. It corrects any inaccuracies from LMP-based calculations and gives you and your doctor the most reliable timeline.

Is it better for the baby to be born before or after the due date?

Doctors consider a baby “full term” at 39 weeks of gestation. The ideal window for birth is generally between 39 weeks (“full term”) and 41 weeks (“late term”). While babies born a little earlier (37-38 weeks, or “early term”) usually do very well, waiting until at least 39 weeks gives the brain, lungs, and liver crucial time to fully develop. Going significantly past the due date (beyond 42 weeks, or “post-term”) can carry some risks, which your doctor will monitor closely.

Can I plan my pregnancy to have a specific due date?

Yes, to some extent. If you want to aim for a specific due date, you can use a conception calculator to work backward. It will tell you the approximate date you need to conceive. To achieve this, you would then need to track your ovulation to identify your fertile window and time intercourse accordingly. However, remember that conception isn’t always guaranteed in any given month, so it may take a few tries.

What to Explore Next on Your Journey

Now that you have your estimated due date, you can start planning for the exciting weeks ahead.

• Dive deeper into the beginning of your story with our Pregnancy Conception Calculator.

• Get detailed information about your baby’s development and your body’s changes with this Pregnancy Week-by-Week Guide.

• If you’re planning your family, our Ovulation Calculator can help you pinpoint your most fertile days.