A pregnancy due date calculator works by adding 280 days, or 40 weeks, to the first day of your last period. Enter your date below to find out your estimated due date, when you likely conceived, and how many weeks pregnant you are.
You might have just taken a test and are counting back, or maybe you’re further along than you thought. Knowing your timeline helps you plan for prenatal care and decide your next steps. You can use this calculator no matter what you’re considering.
Pregnancy Due Date Calculator
Choose how you want to calculate, enter a date, and see your estimated due date and how far along you are.
Disclaimer: This calculator only gives a simple estimate. It does not confirm pregnancy and is not medical advice. If you think you might be pregnant, please contact your doctor or a clinic.
Table of Contents
- How is my due date calculated?
- How accurate is a pregnancy due date calculator?
- Can my due date change?
- What if I don’t know the date of my last period?
- How many weeks pregnant am I?
- Pregnancy wheel vs. pregnancy due date calculator
- Why prenatal care matters
- Pregnant and thinking about adoption?
- Free resources for your pregnancy
- Frequently Asked Questions
How is my due date calculated?
There are three main ways to estimate your due date. The best method depends on what information you have.
Last menstrual period (LMP): This is the most common method. Start with the first day of your last period and add 280 days, or 40 weeks. For example, if your last period started on January 1, your estimated due date would be October 8 in a non-leap year. This method assumes a 28-day cycle. If your cycle is longer or shorter, adjust the date by the difference. For example, a 32-day cycle would move your due date four days later.
Conception date: If you know the day you conceived, add 266 days, or 38 weeks. This method can be more accurate if your cycles are irregular or if you tracked ovulation.
Ultrasound: Your provider measures your baby and compares the size to typical growth. An ultrasound in the first trimester is the most reliable way to date a pregnancy, especially if you’re unsure about your last period.
How accurate is a pregnancy due date calculator?
A due date calculator gives you an estimate, not an exact date. Only about 4 to 5 percent of babies are born on their due date, so it’s better to think of it as a general window instead of a deadline.
Doctors consider a pregnancy full term from 39 weeks to 40 weeks and 6 days. Our calculator shows this window along with your due date. It’s very common for babies to be born a bit earlier or later.
Can my due date change?
Yes. Your provider might change your due date after an ultrasound or if your cycle isn’t 28 days. These changes are most common in the first trimester, when ultrasounds are most accurate. If your due date moves by a few days, it’s normal and doesn’t mean anything is wrong.
What if I don’t know the date of my last period?
This happens often, especially if your cycles are irregular or you found out about your pregnancy later than expected. Here are some options:
- Estimate as closely as you can and use the calculator for a rough idea.
- Visit a doctor, clinic, or pregnancy center. A dating ultrasound can estimate how far along you are.
- Call or text Lifetime Adoption at 1-800-923-6784, and we can help you find a provider near you.
How many weeks pregnant am I?
Pregnancy is measured from the first day of your last period, not from conception. This means you are considered “two weeks pregnant” on the day you conceive. The calculator above figures this out for you and also shows your trimester.
| Trimester | Weeks |
|---|---|
| First trimester | Through 13 weeks 6 days |
| Second trimester | 14 weeks 0 days to 27 weeks 6 days |
| Third trimester | 28 weeks until birth |
Want to know what your baby is doing at each stage? See our guide to fetal development.
Pregnancy wheel vs. pregnancy due date calculator
A pregnancy wheel is a small circular calendar that uses your last period to estimate your due date. It works the same way as an online calculator, but you can carry it with you. Many wheels also show your baby’s estimated weight and length each week, ovulation timing, and when common tests are usually done.
If you want one, this pregnancy wheel is an affordable option. Like the calculator, a wheel gives only an estimate and cannot confirm a pregnancy.
Why prenatal care matters
Seeing a doctor or midwife regularly helps keep you and your baby healthy. Providers can catch problems early, when they’re easiest to treat. According to WomensHealth.gov, babies born to mothers without prenatal care are 3 times more likely to have a low birth weight. Even if you’ve been pregnant before, every pregnancy is different.
For a typical low-risk pregnancy, visits are usually scheduled like this:
| Stage of pregnancy | How often |
|---|---|
| Until week 28 | About once every 4 weeks |
| Weeks 28 to 36 | About every 2 weeks |
| Week 36 until birth | Once a week |
Your provider might want to see you more often. Always follow the schedule your doctor or midwife recommends.
Having trouble getting care? Many women are uninsured, unsure where to start, or have trouble getting to appointments. Lifetime Adoption can help you find a doctor and explore insurance options. Just call or text us anytime at 1-800-923-6784. You can also search for a clinic near you at OptionLine.org.
Pregnant and thinking about adoption?
You can choose adoption at any stage of pregnancy. Whether you just found out or are already several months along, you decide when you’re ready to start. With modern adoption, you are in control of the whole process.
You get real choices, including:
- Choosing the adoptive family for your child
- Deciding how much contact you want with the family and your child, before and after the adoption
- Creating an adoption plan that fits your goals for your child’s future
You can take things at your own pace. Lifetime Adoption will never pressure you into a decision you’re not comfortable with. If you’re still figuring out how to tell your loved ones, this guide on sharing news about an unplanned pregnancy may help.
Free resources for your pregnancy
- Open Adoption app: a free phone app for browsing adoptive families and researching adoption as you decide if adoption is right for you.
- Free eBook: So I Was Thinking About Adoption is a short and easy read that explains your options.
- Planning Kit: This free toolkit will be so useful as you take the next step in your research, or get started on an adoption plan. The kit includes stories from women who have chosen adoption, answers to your adoption questions, and details about about what the adoption process is like.
- Birth Mother Blog: Find new articles every week about pregnancy and your choices.
Frequently Asked Questions
Can I choose adoption at any stage of pregnancy?
Yes. You can choose adoption at any stage of pregnancy. You decide when to start, pick the adoptive family, and choose how much contact you want.
Does a due date calculator confirm that I’m pregnant?
No. A calculator or pregnancy wheel only does the math based on a date. You need a pregnancy test, clinic visit, or doctor’s appointment to confirm a pregnancy.
What is a pregnancy wheel?
A pregnancy wheel is a physical or visual tool that estimates your due date, how far along you are, and key pregnancy milestones, usually starting from the first day of your last period.
Is a pregnancy wheel the same as a due date calculator?
They use the same math. A pregnancy wheel is usually a physical tool, while a due date calculator is digital.
How do I know how many weeks pregnant I am?
Pregnancy weeks are counted from the first day of your last period. The calculator above shows your weeks and days based on today’s date.
Can a pregnancy wheel or calculator help me plan prenatal care?
Yes. It can help you estimate when appointments, screenings, and milestones might happen. Your doctor or midwife should always set your actual schedule.
Is a due date calculator useful if I’m considering adoption?
Yes. Knowing how far along you are helps you see what options and support are available at each stage. There’s no wrong time to ask questions.
Questions about your due date or your options?
We care about you and your baby. Call or text Lifetime Adoption at 1-800-923-6784 any time.
Editor’s Note: This article was originally published on August 30, 2019, and has since been updated.
As Vice President of Lifetime Adoption, Heather Featherston holds an MBA and is passionate about working with those facing adoption, pregnancy, and parenting issues. Heather has conducted training for birth parent advocates, spoken to professional groups, and has appeared on television and radio to discuss the multiple aspects of adoption. She has provided one-on-one support to women and hopeful adoptive parents working through adoption decisions.
Since 2002, she has been helping pregnant women and others in crisis to learn more about adoption. Heather also trains and speaks nationwide to pregnancy clinics to effectively meet the needs of women who want to explore adoption for their child. Today, she continues to address the concerns women have about adoption and supports the needs of women who choose adoption for their child.
As a published author of the book Called to Adoption, Featherston loves to see God’s hand at work every day as she helps children and families come together through adoption.
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