Page last reviewed: 29 April 2021 Show Pregnancy > Due Date Calculator When is your baby due? Use this pregnancy calculator to find your due date based on the date of your last menstrual period, conception date, IVF 3-day or 5-day transfer date or date of your last ultrasound. Most pregnancies last around 40 weeks (or 38 weeks from conception), so typically the best way to estimate your due date is to count 40 weeks, or 280 days, from the first day of your last menstrual period (LMP). You could also subtract three months from the first day of your last period and add seven days. The first day of your LMP is how most health care providers estimate a baby's due date. But remember, it's only an estimated due date, not a deadline for your baby to arrive. Just 4 percent of babies are born on their estimated due date. If you've been tracking ovulation symptoms or have been using ovulation test strips, then you may be able to use your conception date to calculate your pregnancy due date. Just add 266 days to get your estimated due date (or select "Conception Date" from the menu above, and let our Due Date Calculator do the math for you). If you conceived through in vitro fertilization (IVF), you can calculate your due date using your IVF transfer date. Most embryo transfers occur either three days or five days after egg retrieval and fertilization. If you had a day-three transfer, count 263 days from the transfer date to calculate your due date, and if you had a day-five transfer, count 261 days. (Or select "IVF" from the menu above.) Even if you can’t pinpoint when you conceived, forget the day of your last menstrual period or aren’t sure when ovulation occurred, other clues can help you and your practitioner determine your due date at your first prenatal appointment, including:
Whether you're trying to avoid being very pregnant in the middle of summer or are a teacher who wants to maximize time off with your little one, 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 our 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. Yes, your due date can change. While it’s definitely not a reason to worry, your doctor may change your due date for a number of reasons as your pregnancy progresses. It may be that you have irregular periods and your early ultrasound dating was off, or that your first ultrasound was in the second trimester. 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. Find advice, support and good company (and some stuff just for fun). The educational health content on What To Expect is reviewed by our medical review board and team of experts to be up-to-date and in line with the latest evidence-based medical information and accepted health guidelines, including the medically reviewed What to Expect books by Heidi Murkoff. This educational content is not medical or diagnostic advice. Use of this site is subject to our terms of use and privacy policy. © 2022 Everyday Health, Inc A property of
To find out your due date, you just need to select the date of the first day of your last period on our pregnancy calculator tool, adjust your average cycle length and click 'submit’. Your cycle length is the number of days between your periods, counting the first day of your period until the day before your next period starts. You will then receive your estimated due date and the option to sign-up to our pregnancy email. This weekly email gives you fun pregnancy facts, useful tips and great recipe ideas to help you and your baby have the healthiest possible pregnancy. Are you in early pregnancy? Find out all you need to know about pregnancy from week 4 onwards. What if I have irregular periods?If you were having irregular periods before you got pregnant, you can still use the pregnancy calculator. Just choose your average cycle length. But bear in mind that an ultrasound will be the most accurate way of predicting your due date. How accurate is the due date?The pregnancy calculator gives you an approximate due date. It is worked out by adding 280 days (40 weeks) to the first day of your last menstrual period. This is based on a 28-day cycle but is adjusted for longer or shorter cycles. Your period and ovulation are counted as the first 2 weeks of pregnancy. If you have the baby on your due date, your baby has been growing for 38 weeks, not 40, but you are still classed as 40 weeks pregnant. Remember that only around 5% of babies are born on their due date so it’s just an estimation. Will I get a more accurate due date later in the pregnancy?You will have your first appointment with the midwife, the 'booking appointment', by 10 weeks. At that appointment, you will be offered an ultrasound scan – this is often called the dating scan. This scan will check how many weeks pregnant you are and work out a more accurate due date. You’ll also be able to find out whether you’re having more than 1 baby and how your baby is developing. But if you're impatient to know when your baby will arrive, our due date calculator can give you an estimated due date now! What should I do next?If you don’t already have a midwife, you may be able to self-refer to your local maternity unit directly for your antenatal care. Visit your local hospital’s website to find out more. Speak to your GP if you can’t self-refer or if you think your pregnancy may be high-risk. For example, if you have a long-term condition, had complications in a previous pregnancy or experienced a late miscarriage or stillbirth. Your GP will tell the midwifery team you are pregnant. You will be given a date for your first appointment with a midwife. This should happen before you are 10 weeks pregnant. We know pregnancy can be an overwhelming time. We created our Healthy Pregnancy tool to try to take away some of this anxiety by giving you a personalised set of tips for your pregnancy. |