• Contact us
• About us
• A-Z topics
• Symptom Checker
• Service Finder
• Linking to us
• Information partners
• Terms of use
• Privacy

Pregnancy, Birth and Baby is funded by the Australian Government and operated by Healthdirect Australia.

Pregnancy, Birth and Baby is provided on behalf of the Department of Health

Pregnancy, Birth and Baby’s information and advice are developed and managed within a rigorous clinical governance framework. This website is certified by the Health On The Net (HON) foundation, the standard for trustworthy health information.

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.

This information is for your general information and use only and is not intended to be used as medical advice and should not be used to diagnose, treat, cure or prevent any medical condition, nor should it be used for therapeutic purposes.

The information is not a substitute for independent professional advice and should not be used as an alternative to professional health care. If you have a particular medical problem, please consult a healthcare professional.

Except as permitted under the Copyright Act 1968, this publication or any part of it may not be reproduced, altered, adapted, stored and/or distributed in any form or by any means without the prior written permission of Healthdirect Australia.

Support for this browser is being discontinued for this site

• Internet Explorer 11 and lower

We currently support Microsoft Edge, Chrome, Firefox and Safari. For more information, please visit the links below:

• Chrome by Google
• Firefox by Mozilla
• Microsoft Edge
• Safari by Apple

You are welcome to continue browsing this site with this browser. Some features, tools or interaction may not work correctly.

Calculate your due date: How to find your baby's due date

Choose a calculation method Last periodConception dateI know my due date

First day of my last period

BabyCenter's Due Date Calculator

Use our pregnancy due date calculator by plugging in either the date of your last menstrual cycle or the date you know you conceived. The calculator will do the rest.

How is my due date calculated?

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

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. So, 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?

First day of your last period

The most common way to calculate your pregnancy due date is by counting 40 weeks from the first day of your last menstrual period (LMP). And that's how most healthcare providers do it.

If your menstrual cycle length is the average length (28-day cycle), your menstrual cycle 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 menstrual cycle actually is or when you think you might have conceived. But generally speaking, women typically ovulate about two weeks after their menstrual cycle starts. And women are more likely to know when their last period started than the day they ovulated.

Conception date

If you do happen to know precisely when you conceived – say, if you were using an ovulation predictor kit or tracking your ovulation symptoms – you can calculate your pregnancy due date based on your conception date. Just choose that calculation method from the pulldown above and put in your date.

Note: Again, you don't necessarily conceive on the day you have sex.

IVF transfer date

If you conceived through IVF, you can calculate your due date using your IVF transfer date. If you had a Day 5 embryo transfer, count 261 days from your transfer date. If you had a Day 3 embryo transfer, count 263 days.

Can my due date change?

Your healthcare provider might revise your due date if your baby is measured during a first trimester ultrasound scan and found to be much bigger or smaller than expected for gestational age. This is more likely to happen if you have an irregular menstrual cycle length that makes it hard to pinpoint the date of conception.

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.

What if I already know my due date?

If you already know your due date, you can use this calculator to see your pregnancy timeline. It will tell you when you'll hit various milestones, and when you may be due for prenatal tests and prenatal visits. You'll also find what your baby's sign and birthstone will probably be and which famous people 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 tool or from your doctor or midwife. Only 1 in 20 women delivers on their due date. You're just as likely to go into labor any day during the two weeks before or after.

Want more information about how the weeks, months, and trimesters of pregnancy are counted? See our pregnancy timing chart.

How soon can I take a pregnancy test?

With all this talk about pregnancy due dates, 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.

Read more

• Your pregnancy, week by week
• Your first trimester pregnancy checklist
• Pregnancy Weight Gain Calculator
• Ovulation Calculator
• See all tools

Gestational age.

CONTENTS

1. What is a calculator?
2. How does the calculator work?
3. Other ways to determine and confirm the due date.
4. How accurate is the calculator?

What is a calculator?

In most cases, women do not know the exact date of conception, but they can with great certainty to say when the last menstrual cycle began. The first the day of the last menstruation is the starting point. Well, then 9 comes into play0003 pregnancy calculator - a program that makes a lot of calculations for you and answering almost all questions of interest to the expectant mother :

• when was the conception approximately;
• what is the estimated date of delivery;
• what is the exact week now and how much is left until the birth;
• how a child develops, what size it is, what it already does in the womb and what skills it has.

Calculator free, always available online, easy to use, has concise and understandable interface, will not let you make arithmetic errors and displays results in a visual and interesting way. In addition, you can always check the accuracy calculator, independently making calculations according to well-known obstetric techniques, which we present below. nine0005

To calculate the gestational age and the expected date of delivery, a woman needs to enter in the calculator, only the date of the first day of the last menstruation (LPM) in the format "day month Year". If you enter the last day of your period or a known date conception, the calculator will show completely different results, you need to enter exactly the start date last menses.

The calculator calculates the obstetric period - this is when the first day of menstruation is considered like the first day of pregnancy. It is by obstetric term that gynecologists track the development fetus, prescribe tests and examinations. nine0005

The gestational age in the calculation results of the calculator is shown in weeks, this is the most simple and convenient interval. There are other generally accepted intervals for dividing such a large period - months (10 lunar months of 28 days) and trimesters. The trimesters divide the process intrauterine gestation into three phases of 13 weeks each.

The results display the exact time in weeks and days, a brief description of the development of the fetus, the height and weight for the calculated week are indicated, which organs are being formed, what can already be felt and do baby. A link is provided to the full article with colorful illustrations, telling about the condition of the fetus and mother, tests and examinations, recommended diet, possible problems and ways to overcome them. You will always know what to prepare for. nine0005

This calculation displays both fetal ages: the so-called "gestational" fetal age (menstrual), which is different from the so-called "ovulation" age (fertilization), it is two weeks less and is counted from the estimated date of conception. Therefore, all the details fetal development and well-being of women are considered from week to week, starting precisely from the third week.

In addition, you will know how many days are left before childbirth, under what sign of the zodiac and in what year of the Chinese calendar your baby will be born, by clicking on additional links you can determine the color of the eyes, the blood type of the child. nine0005

Depending on the week, additional links to calculators for checking ultrasound results are displayed, hCG hormone levels, blood test results, weight gain rates. If you wish, you can calculate an individual calendar of analyzes and examinations, both for mother and child.

Starting in the second or third trimester, you can find out about your benefits and calculate your benefits. amounts. For working mothers, it is possible to determine the date of maternity leave and find out if you are entitled to annual leave leave before the decree. nine0005

Whatever week you are, the calculator will offer you to test your knowledge using interactive tests "Care of a newborn", "Feeding of newborns", "Tests and examinations of pregnant women", "Rights of pregnant women". You will just have time to fill in the gaps and improve your knowledge on these important topics.

The calculator will also calculate the estimated date of conception of the child, by which, using Chinese gender calendar, you can find out who you will be - a girl or a boy. According to the results of the ultrasound, it will be interesting to know whether the prediction came true. nine0005

How does a calculator work?

All calculations of our calculator are based on the obstetric calculation method, as the most accurate, scientifically based and universally accepted method for calculating gestational age. other methods, for example, a report from the day of intercourse or from ovulation cannot be considered reliably accurate due to the characteristics of the reproductive system.

Cycle length may vary from woman to woman, one has 21 days, another has 34, moreover, in the same woman, the cycle may be irregular and fluctuate in duration during years for various reasons. On average, most women have a menstrual cycle is 28 days. nine0005

But one thing is common to all: conception of a child is possible only during ovulation - if there is no mature egg, then conception will not occur.

At the beginning of the cycle, a follicle forms on the surface of the ovary, inside which the female matures. sex cell. In the middle of the cycle, the follicle sac ruptures under the influence of strictly defined hormones. and allows spermatozoa access to the oocyte.

After ovulation, the female gamete lives from 24 to 36 hours, at which time conception must occur, otherwise the cell dies. This process is repeated every cycle. nine0005

It turns out, regardless of the length of the cycle, nature allocates only one or two days for the process of conception. However, this does not mean that sexual intercourse can lead to pregnancy only during the hours when the oocyte lives. Not, due to the ability of spermatozoa to survive for a long time in the female body, sex even 3-4 days before release the egg can lead to fertilization immediately after its release from the follicle. With active sexual life in general it is impossible to determine whether sexual intercourse before, during or after ovulation led to conception. nine0005

Therefore, in obstetric practice it is considered that conception occurs during the period of ovulation - 14 days before before the end of the menstrual cycle. And again, we are faced with a harsh reality here - a woman ovulates can happen both earlier and later than the above day. Based on all this, it is customary to count from the date of the last menstruation, this is both easier, and the woman usually remembers this date.

Thus, according to the obstetric standard, the first day of the last menstruation is the first day pregnancy, and the day of conception falls approximately at the end of the second week. If a woman finds out about the delay, then this is already the 4th week and the gynecologist, regarding a week-long delay, is already setting a deadline of 5 weeks. nine0005

Our online calculator is based on this obstetric method. Weeks are normal calendar months, and obstetric months, each of them has exactly 4 calendar weeks.

Pregnancy lasts an average of 40 weeks or 10 obstetric months well-known 9 months .

I	1	20087	8	9	10
	11	12	13	14	15	16	17	18	19	20
II	21	22	23	24	25	26	27	28	29
III	31			32	32	32																									0087	35	36	37	38	39	40

for which a woman is simply at three stages of understanding and the fetus, each trimester has its own characteristics. For example, in the first trimester there is a rapid the formation and development of the organs of the child, then miscarriages most often occur. In the third trimester it is necessary to prepare for the manifestation of possible problems associated with pregnancy - hypertension, toxicosis. nine0005

There are 3 calendar months in one trimester, the first trimester is 1-13 weeks, the second trimester is 14-27 weeks, the third is 28-42 weeks .

1st trimester

2nd trimester

3rd trimester

or all three ways:

1. Add the average duration of pregnancy, which is 280 days, to the first day of the last menstruation.
2. Add 9calendar months to the first day of the last menstruation and subtract 7 days from the resulting date.
3. Subtract three months from the first day of your last period and add 7 days to the result.

Absolutely the same way they calculate the term in the antenatal clinic, the same methods are used in round paper obstetric calendars.

Other ways to determine and confirm the due date

There are no other scientific methods for determining the gestational age and due date. But there are methods using which can be confirmed or corrected. Again, almost all of them are based on the obstetric method, statistical data and data from an objective examination of the expectant mother. nine0005

The main objective sign of pregnancy is an increase in the size of the uterus, which in the first months is determined by vaginal examination, and after the third - by the height of the fundus of the uterus. By the end 1st month (28 days) the uterus corresponds to the size of a chicken egg, 2nd month (56 days) - an average fist women, then each month has its own size. There is no need to talk about the accuracy of this method.

Additional information about the due date and due date can be obtained by measuring the length of the fetus. measurements produce a tazomer in the position of a woman lying on her back. One button of the tazomer is placed on the lower pole head, the second - at the bottom of the uterus. Calculations are made using a special formula, but the result is also approximate due to different assumptions, for example, the thickness of the abdominal walls can be taken in both 3 and 5 cm.

According to the level of hCG

At the earliest stages (from the 4th to the 8th week), pregnancy is confirmed by the level of hCG. By date of conception or, if it is unknown, then the obstetric period is determined from the first day of the last menstruation, and from it the hCG rate is determined. If the pregnancy is proceeding normally, then the hormone levels will correspond, or rather be within the range of valid values. The accuracy of this method is very low, as hormone levels are indicated in a wide range and the main thing for which this method is used is to determine the normal development fetus. The hCG level may not fall within acceptable limits, but if it doubles in two days, the fetus is considered to be developing normally. As you can see, this method is not always possible to use. nine0005

Ultrasonography

Ultrasound examination can also confirm pregnancy, this method is used to detect fetal egg and registration of heartbeats. Ultrasonography is currently the only method allowing with the greatest degree of accuracy to establish the gestational age and follow the development of the fetus, starting from the very first weeks of its intrauterine development.

The date of the last menstruation is entered into the ultrasound machine and, upon further scanning, the doctor determines how embryonic development corresponds to the obstetric period. Statistical tables of sizes are set in these devices fruit for each week and day. nine0005

In early pregnancy, when embryos develop at about the same rate, it is easier to compare their sizes are with average statistical norms and it is possible to more accurately determine the age. In this case, the doctor evaluates parameters of the baby, compares with the tables, gets the gestational age and, after adding two weeks, calculates obstetric term. If a woman did not remember the start date of the last menstruation, then the only way to determine the date pregnancy.

Later, when the fetus begins to develop according to its individual genetic program laid down by the parents (large or petite build, large or small height), it becomes more difficult to accurately determine the week. nine0005

By movements

In the middle of pregnancy, usually at 20 weeks in nulliparous women and at 18 weeks in multiparous women first fetal movement. Before the advent of ultrasound, this method was used without alternative to confirm the term pregnancy, there was no other way. Now this is an auxiliary method, it cannot be considered exact, since not everyone is able to recognize the first stirring. Currently no longer used for its intended purpose.

How accurate is the calculator? nine0017

The same as the calculator, the method of calculating the gestational age is used by an obstetrician-gynecologist in the women's consultations, in a hospital for conservation, in a maternity hospital, in medical equipment - ultrasound machines and laboratory equipment. That is, the calculator is as accurate as medical equipment and an obstetrician. If the obstetrician, due to an irregular cycle, early or late ovulation can make a small error, then this will happen with the calculator, because the calculation method is used one. In most cases, this method, and therefore the calculator, is very accurate. nine0005

It is important to remember that the expected date of delivery (ED) is not an exact, but an approximate calculated date, the term itself includes the word "alleged". Only one woman out of twenty gives birth exactly on the calculated day. The rest are giving birth. one to two weeks earlier or later than expected.

It is considered absolutely normal that labor can begin on any day from 38 to 42 weeks and there is no way to know for sure calculate this date. It all depends on nature, mother and child.

Calculate due date - pregnancy calculator on satya Mamovedia | Mamovediya

Calculate due date - pregnancy calculator on satya Mamovediya | Mamovediya - about the health and development of the child

Calculate the date of birth of your child and the dates of tests and examinations

The beginning of the last menstruation

Average cycle length

* Approximate calculation for the average cycle length and the onset of ovulation - plus 14 days before the start of the last menstruation. nine0005

** Full 40 weeks

You at pregnancy Week

Date	Date	What should be done
POSITION OF PREDERATION (5 weeks)	9008 9008 9	Beginning of organ formation (week 5)
Major organs formed (week 10)
End of third trimester (12 weeks). During this period, you must be registered in the antenatal clinic		At the first examination by an obstetrician-gynecologist, an "Individual card of a pregnant woman and a puerperal woman" (form No. 111 / y) and an exchange card (form No. 113 / y) are filled out. An exchange card is issued to a pregnant woman in her hands from the moment of registration. She should always be with you in case you have to be in the hospital ahead of time. they will also clarify the age, state of health of a person, his blood type and Rh affiliation, as well as the presence of harmful factors associated with the profession and bad habits of spouses. In the presence of heavy or harmful work, at the first application you are issued a certificate of the need for exemption from harmful and difficult working conditions. You will be weighed, your blood pressure will be measured (on both arms), you will undergo a general therapeutic examination, an external examination of the thyroid and mammary glands for the purpose of diagnosis. Mandatory is an obstetric examination with the measurement of the main dimensions of the pelvis, examination of the vagina. when examining the vagina, it is mandatory to examine the cervix and the walls of the vagina in the mirrors. In women with a physiological course of pregnancy and in the absence of changes in the cervix and vagina, an internal obstetric examination is performed 2 times (when registering and at a gestational age of 30 weeks). The frequency of internal obstetric examinations is determined by indicators. The primary complex of laboratory examination of a pregnant woman includes a clinical blood test, a general urinalysis, determination of the blood group and Rh factor, a blood test for syphilis, HIV (by consent), bacterioscopic examination of smears from the vagina, cervical canal, urethra . The district obstetrician-gynecologist conducts pre- and post-test consultations for a pregnant woman on HIV testing. The first ultrasound with the obligatory determination of the size of the cervical fold (with the exception of Down and Edwards syndrome). If you are at risk of developing gestational diabetes, then a screening glucose tolerance test is necessary. If there are indications, you may be referred for further additional examination: blood tests and hepatitis B and C, tests for infections of the perinatal period (toxoplasmosis, rubella, cytomegalovirus, herpes) , Grove's biochemical study, hemostasiogram, etc. Indications for examination for infections: - chronic inflammatory diseases of the genitals - acute respiratory viral infections during this pregnancy - history of spontaneous miscarriage - history of stillbirth - polyhydramnios, low water during this pregnancy - pathological changes in the cervix (cervical erosion, cervical dysplasia and etc.) - History of infertility In order to prevent and early diagnosis of hereditary and congenital pathology of the fetus, according to indications, you must be referred for a medical genetic examination. and weeks you should attend antenatal clinic monthly. End of embryonic period
Week 13		Repeated visit to the local obstetrician-gynecologist with the results of laboratory examination and consultations of related specialists. Determination of the obstetric and perinatal risk group by scoring
Week 18		Second ultrasound, exclusion of Down syndrome, Edwards syndrome and neural tube defects. Screening test for alpha-fetoprotein, chorionic gonadotropin, estriol - according to indications
Week 20		Definition of obstetric and perinatal risk group by scoring. The first sensation of the fetal move in women giving birth to
The end of the second trimester (27 week)
28 weeks		The second study for syphilis, HBS agriculture of the assumed doubles of the gesto -risk of the gestois
30 week		Vaginal examination (internal obstetric examination) Three-quarters of due date Prenatal leave for most pregnant women. When applying for maternity leave, the obstetrician-gynecologist is guided by the procedure for issuing a certificate of incapacity for work in connection with pregnancy and childbirth (Order of the Ministry of Health of Ukraine dated November 13, 2001 No. 455 "On approval of the Instructions on the procedure for issuing documents certifying temporary disability of citizens"). From this period until delivery, you visit the antenatal clinic twice a month.Bacterioscopic analysis of discharge from three points (vagina, cervical canal, urethra) Before each appointment, a general urine test
Ultrasound 3 (32 weeks)		Determination of the obstetric and perinatal risk group by determining the scoring At the period of 32-36 weeks, the third ultrasound examination is performed on the following indicators: fetal growth retardation syndrome, chronic fetoplacental insufficiency, pathological changes in cardiogram (CTG), severe obstetric and extragenital pathology to determine the biophysical profile of the fetus
38 week		Term pregnancy

* Approximate calculation based on average cycle length and onset of ovulation - plus 14 days before the start of the last menstrual period.

---

Learn more

• 
  Babies first crawl
• 
  Easiest signs of pregnancy
• 
  Newborn baby yellow eye
• 
  23 months old milestones
• 
  Try to make a baby
• 
  How to get child support off your credit report
• 
  Can you have a baby at 26 weeks
• 
  How to do a membrane sweep yourself
• 
  What is placenta used for
• 
  In labor having a baby
• 
  Down syndrome diagnosis test