Weeks and Trimesters How Many Months Pregnant Are You? Convert your due date to the weeks, months, and trimesters in your pregnancy By Robin Elise Weiss, PhD, MPH Robin Elise Weiss, PhD, MPH LinkedIn Twitter Robin Elise Weiss, PhD, MPH is a professor, author, childbirth and postpartum educator, certified doula, and lactation counselor. Learn about our editorial process Updated on January 02, 2023 Medically reviewed by Rachel Gurevich, RN Medically reviewed by Rachel Gurevich, RN Facebook LinkedIn Twitter Rachel Gurevich is a fertility advocate, author, and recipient of The Hope Award for Achievement, from Resolve: The National Infertility Association. Learn about our Medical Review Board Print Verywell / Alison Czinkota Table of Contents View All Table of Contents Pregnancy Weeks vs. Months Pregnancy Trimesters Counting Pregnancy Weeks Counting Pregnancy Months As soon as you find out you're pregnant, you'll probably start counting nine months on your fingers to figure out when your baby will be born. But then your healthcare provider might mention that you're likely to go into labor once your 40 weeks along, and things don't seem to line up, because 40 weeks sounds more like 10 months. Your gestational period is in fact 40 weeks long, but it starts counting on the first day of your last period. You aren't actually pregnant during weeks 1 and 2, and by the time you see a positive result on a pregnancy test, you are already considered four weeks pregnant. The first month has already passed! You can count your gestational period in weeks or months. Your healthcare provider will use weeks, but you might start using months in conversation when you get further along. Your friends and coworkers might find "I'm 8 months" easier to understand than "I'm 32 weeks." In this article, we explain how to figure out how many weeks or months along you are throughout your pregnancy. Pregnancy Weeks vs. Months Planning for a nine-month pregnancy can be confusing if you look at the total number of weeks in the average pregnancy. When you break down the numbers, it would seem that pregnancy lasts 10 months, not nine. 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, there is also the issue of when you actually became pregnant. While an exact date may not matter to everyone, you can estimate the date based on testing. By the time you have a positive pregnancy test, you are usually about four 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. Pregnancy Trimesters While you might explain your pregnancy in weeks or months, many expectant moms also describe their pregnancy in trimesters. Each trimester lasts about 12 to 13 weeks. There are three trimesters in a full-term pregnancy. First Trimester This early trimester usually includes weeks 1 to 13, or months 1 to 3. This is considered a short trimester because many women don't know that they are expecting during the early weeks of pregnancy. Second Trimester The middle trimester usually includes weeks 14 to 27, or months 4 to 6. Many moms consider this to be the easiest and most comfortable trimester. Third Trimester Your last trimester may include weeks 28 to 40, or months 7 to 9. But many women go into labor before week 40 and some may stay pregnant a week or two longer. You due date is an estimate of when your baby is likely to be born. It is 40 weeks (280 days) after the first day of your last menstrual period. But anywhere from 37 to 42 weeks of gestation falls within the normal range, known as full-term.Babies born before 37 weeks gestation are considered pre-term and will need specialized care. About 8% of babies will be born pre-term. If you go past 42 weeks gestation, your healthcare provider will likely induce your labor to avoid complications related to late-term delivery. Counting Pregnancy Weeks Your practitioner will count your pregnancy in weeks to help them more accurately assess the health of you and your baby. If you are unclear about your pregnancy week, be sure to ask for your provider's guidance. Once you get your estimated weeks of pregnancy, you can use that information and your due date to plot your pregnancy by week at home. To do this, note the day of the week that your baby is due. Then choose that day of the week in your current week of pregnancy and start counting forward. For example, if your due date is on a Monday and you are currently in your fourth week of pregnancy, note that date on your calendar with "week 4." Then note that on the following Monday you'll be five weeks along. The Monday after that you would be six weeks along. Every Monday moving forward you gain a week of pregnancy, until around 40 weeks. 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 is usually easiest to reply in months. But the answer can vary. There are different ways to lay out the months of pregnancy depending on whether you emphasize the first trimester or the last trimester. Here are some common breakdowns of the months of pregnancy. Pregnancy by Month: Emphasis on First Trimester This monthly breakdown assumes that early pregnancy is very important. Since many women aren't aware that they are pregnant during the first two 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 every moment from the last normal menstrual cycle and considers the fact that some women 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 Length of a Month This breakdown takes the date of your last menstrual period and counts until the same date of the subsequent months. For example: If the date of your last menstrual period was April 17: Month 1: April 17 through May 16Month 2: May 17 through June 16Month 3: June 17 through July 16Month 4: July 17 through August 16Month 5: August 17 through September 16Month 6: September 17 through October 16Month 7: October 17 through November 16Month 8: November 17 through December 16Month 9: December 17+ As you can see from the three schedules, there are different ways to describe which month of pregnancy you are in based on how you interpret the weeks. There is no right or wrong way to answer when people want to know how far along you are. Simply provide the week or month you feel is appropriate for your gestational age. A Word From Verywell Remember that when people inquire about your pregnancy progress, there is no need to explain the difference between weeks and months. Whether you answer five months or six months on the chart above, you are still 24 weeks pregnant. Simply choose the answer that best suits you. Sometimes you might feel very pregnant and six months makes you feel better than five months. Or, perhaps you are not anxious for the pregnancy to be over and you would prefer to be five months pregnant. This mental game is one that can help you stay sane through a potentially discombobulating time. 4 Sources Verywell Family uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy. Eunice Kennedy Shriver National Institute of Child Health and Human Development. About pregnancy. Due Date Calculator. National Health Service. Premature Labor and Birth. National Health Service. Galal, M., et al. “Postterm Pregnancy.” Facts, Views & Vision in ObGyn, vol. 4, no. 3, 2012, pp. 175–87. Additional Reading Jukic AM, Baird DD, Weinberg CR, McConnaughey DR, Wilcox AJ. Length of human pregnancy and contributors to its natural variation. Hum Reprod. 2013;28(10):2848-2855. doi:10.1093/humrep/det297 By Robin Elise Weiss, PhD, MPH Robin Elise Weiss, PhD, MPH is a professor, author, childbirth and postpartum educator, certified doula, and lactation counselor. See Our Editorial Process Meet Our Review Board Share Feedback Was this page helpful? Thanks for your feedback! What is your feedback? Other Helpful Report an Error Submit