Due date calculator

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Calculate your due date

With our handy due date calculator, you can easily calculate your due date. The only information needed is the first day of your last period.

In case of insemination or egg retrieval, subtract 14 days from that date to get a more accurate due date.

Calculate your due date today and learn more about your due date and how far along you are in your pregnancy.

Worth knowing

Here we answer some of the most frequently asked questions about pregnancy and due dates.

Pregnant week by week – what happens?

Something new happens every week of pregnancy. In the first few weeks, you don’t notice the baby very much. But there is still a lot of progress in the baby’s size and development. Almost halfway through the pregnancy, most women will have felt life. At the same time, the baby also starts to respond to sounds.

How many weeks are you pregnant?

We all know that a pregnancy lasts 9 months. But how many weeks is that really?

A typical pregnancy lasts 40 weeks. Some give birth early and others go over their due date. For some, it can feel like a long time and for others, time just flies by way too fast. It often depends on whether the pregnancy is hard on the woman’s body, because 40 weeks can feel like a long time.

Keep track with a pregnancy calendar

One idea to help you pass the time is to make a pregnancy calendar. Hang up a calendar at home where you tick off the weeks. Each week you can check our week-by-week timeline at the bottom of the page, where you can read more about what’s happening inside your belly right now.

Can I plan my due date?

Whether you’re trying to avoid being pregnant in the middle of summer or want to plan for free time with your little one, you can try to plan your due date.

If you are able to get pregnant without help, just remember that it’s difficult to plan exactly when labour will happen.

Can my due date change?

Yes, your due date can change. While it’s definitely not a cause for concern, your doctor may change your due date for a number of reasons depending on how your pregnancy develops.

It could be that your early ultrasound scan was inaccurate. It could also be that your levels of alpha-fetoprotein (AFP), a protein made by the baby, are outside the usual range.

Talk to us if you have any questions.

Your pregnancy – week by week:

Week 4.

The developing fetus is approximately 1 mm in diameter. The fetal system has grown into the lining of the uterus. The placenta forms and the fetus receives its nutrition and oxygen through the placenta. Waste products are removed through the placenta. The spinal cord is being formed, part of which will later become the brain.

Week 5.

The fetus is now 2.5 mm in diameter. A primitive spinal cord has now been formed and closed. The first blood vessels and blood cells are forming, although they are still immature. A simple heart, shaped like a tube, has formed and has now started to beat. All organs slowly begin to take shape.

Week 6.

The fetus is now 2.5 mm from head to buttom. The liver, lungs, spleen, pancreas, and thyroid gland are forming. The digestive system now consists of a foregut, midgut, and hindgut. These parts will later develop into the esophagus, stomach, and the final intestinal system. The umbilical cord has now formed. The heart still has only one chamber, and the circulatory system is continuing to develop. The head is taking shape, but it is still facing forward.

Week 7.

The fetus measures 5.5 mm from head to the buttom—this is also called the breech height. The legs can be interpreted as thigh, calf, and foot. The limbs are still developing. The eyes can be seen as indentations on either side of the fetus’s head. The foregut develops into the esophagus and stomach.

Week 8.

The fetus is 11 mm in breech height (measured from head to buttom) and weighs 1.1 grams. The heart is now in the thorax and the fetus has a neck. Hands and feet can be seen as small lumps. The mouth opening is formed. The inner ear is forming. The nose is visible and the mouth is visible as a slit. The eyes are far apart, but on opposite sides.

Week 9.

The fetus is 17 mm in breech height and weighs 2.7 grams. The neck is taking shape and the head is gradually turning upwards. Muscles are being formed. The heart septum and four heart chambers have formed. Both baby teeth and permanent teeth are taking shape. The nervous system continues to develop. The internal genitalia are forming in both sexes. Girls now have immature eggs in their ovaries. There are around 10 million immature eggs. At birth, the number has dropped to 1 million and by puberty, there are 400,000 eggs. The fetus responds to touch.

Week 10.

The fetus is 25 mm in breech height (measured from head to bottom) and weighs 4.6 grams. The eyes are now located on either side of the head and the cheeks are visible. The jaws are developed. The heart is fully developed. It beats 140-150 beats per minute. Eyelids are now forming. Fingers and toes can be seen. The nose and mouth are now close together.

Week 11.

The fetus is 32 mm in breech height (measured from head to buttom) and weighs 7.9 grams. The mouth is taking shape and the upper lip is visible. The ears and nose have become clearer. The external genitalia can be recognized and testicles can be distinguished from ovaries. Boys’ testicles now produce the male sex hormone, testosterone.

Week 12.

The fetus is 43 mm in breech height (measured from head to buttom) and weighs 14.2 grams. The outline of 10 baby teeth and 16 permanent teeth is formed. The fetus looks like a child and the head is fully erect. Legs and arms can bend. The fetus swims around in the amniotic fluid.

Week 13.

The fetus is 53 mm in breech height (measured from head to buttom). The face looks more and more like a human. The eyelids are fusing together. The baby can suck on its fingers. The skeleton is developing and bone tissue is forming.

Week 14.

The fetus is 68 mm in breech height (measured from head to buttom) and weighs 45 grams. The cheeks have become clear and the nose looks like a nose. The ears are properly positioned and look like human ears. The eyes are almost correctly placed on the face. The kidneys are now ready to produce urine. Early sweat glands are emerging. External genitals are visible and you can tell the difference between girls and boys. If the fetus’s lips are stroked, it responds with sucking movements.

Week 15.

The fetus is 8.1 cm in breech height (measured from head to buttom). The fetus can move its arms and clench its hands.

Week 16.

The fetus is 10 cm in breech height (measured from head to buttom) and weighs 110 grams. Especially women who have given birth before will feel movement and it feels like little bubbles in the belly. Taste buds are developing. Sweat glands are formed. The fetus can frown and swallow.

Week 17.

The fetus is 11.1 cm in breech height (measured from head to buttom). A heat-regulating fat layer is gradually forming. The fetus can hear sounds.

Week 18.

The fetus is approximately 12 cm in breech height (measured from head to buttom) and weighs 200 grams. Sebaceous glands are formed. Feces, also called meconium, begins to accumulate in the intestines. The retina in the eye is sensitive to light. The girl’s ovaries are now at the pelvic rim. They will only move into the pelvis when the girl is around 8 years old. The fetus can suck on its thumb. The fetus now has a primitive memory and can recognize simple things like specific sounds.

Week 19.

The fetus is 13.4 cm in breech height (measured from head to buttom). Most people have now felt movement. If the fetus has hiccups, they can be felt through the abdomen.

Week 20.

The fetus is 145 mm in breech height (measured from head to bottom). You can distinguish between girls’ and boys’ genitals. The heart beats 120-140 beats per minute. The skin is thin, but keeps getting thicker.

Week 21.

The fetus is 157 mm in breech height (measured from head to buttom) and weighs 320 grams. In boys, the testicles have not yet descended into the scrotum but are located in the groin.

Week 22.

The baby is 167 mm in breech height (measured from head to buttom) and weighs 500 grams. Fingernails are gradually forming, followed later by toenails. Fingernails grow fastest. The baby can respond to loud noises. It develops a regular rhythm between sleep and wakefulness. The lungs are developed enough to breathe. The baby grows fine hairs on the face, known as lanugo hair. From here, the hair spreads to the body. Enamel is formed on the teeth. The vagina in girls is now fully developed. The baby responds to touch like a 1-year-old. The baby’s hearing is well-developed and can respond to music and other sounds. Loud noises can be uncomfortable.

Week 23.

The baby is 180 mm in breech height (measured from head to buttom). The baby can now suckle. The brain continues to develop at a rapid pace.

Week 24.

The baby is 192 mm in breech height (measured from head to buttom) and weighs 700 grams. Eyelashes have grown and the eyelids are opening again.

Week 25.

The baby is 202 mm in breech height (measured from head to bottom). The boy’s penis is growing longer. A protective layer of vernix caseosa, also called fetal fat, is forming on the skin.

Week 26.

The baby is 21 cm in breech height (measured from head to buttom) and weighs 900 grams. The intestines are now in place in the pelvis. The baby can open and close its eyes.

Week 27.

The baby is 22 cm in breech height (measured from head to buttom) and weighs 1000 grams. If the baby was born now, it would have a good chance of survival.

Week 28.

The baby is 23 cm in breech height (measured from head to bottom) and weighs 1100 grams. The placenta is now working at its peak. It is approximately 20 cm in diameter and weighs 500 grams. The hairs on the baby’s head have grown quite long.

Week 29.

The baby is 23.7 cm in breech height (measured from head to buttom) and weighs 1300 grams. Certain brain activity can be detected during sleep (REM), indicating that the baby is dreaming.

Week 30.

The baby is 24.5 cm in breech height (measured from head to buttom) and weighs approximately 1500 grams. The boy’s testicles have now reached the groin. The baby’s wrinkled skin is smoothing out more and more. The baby is able to control its own body temperature.

Week 31.

The baby is 25.2 cm in breech height (measured from head to buttom). The baby can distinguish between light and dark. The brain has developed rapidly. All the reflexes that the baby is born with are now present.

Week 32.

The baby is 26.5 cm in breech height (measured from head to buttom) and weighs 1900 grams. In boys, the testicles have now descended into the scrotum. The baby’s fat layer under the skin is thickening. Nails and hair continue to grow. If the baby dislikes something, such as very loud noises, it will kick vigorously.

Week 33.

The baby is 27.6 cm in breech height and weighs 2200 grams. All internal organs are fully developed. Now, it’s mainly the brain that is refining.

Week 34.

The baby is 28.4 cm in breech height and weighs 2400 grams. If born now, the baby would likely be able to survive without complications. The placenta is still functioning, but its role is gradually decreasing. The baby may develop preferences for certain music or sounds. Mom’s or dad’s voice may be soothing.

Week 35.

The baby is 29.3 cm in breech height and weighs 2600 grams. The baby’s muscles and fat tissue continue to grow, making the baby more plump.

Week 36.

The baby is 30 cm in breech height and weighs 2800 grams. The baby is in the birth position, with its head facing downward, which is common for first-time mothers.

Week 37.

The baby is 31 cm in breech height. The mother may experience contractions where the uterus tightens. These contractions help to shorten, soften, and slowly open the cervix, preparing the body for birth.

Week 38.

The baby is 31.6 cm in breech height and weighs 3200 grams. The baby’s skin is no longer wrinkled, but smooth. The fine downy hair that previously covered the baby’s body has disappeared. The baby has assumed its birth position, and are facing downward. However, about 3% of babies are born in a breech position, with the bottom facing down.

Week 39.

The baby is 33 cm in breech height and weighs 3400 grams. The baby is ready to be born, and the parents are likely feeling impatient! Around 12% of births are via cesarean section, though this can vary depending on location. The baby’s nails are now long enough to extend beyond the fingertips. The baby may not move as much because space is getting tight.

Week 40.

The baby is 34 cm in breech height – 55 cm in total length and weighs 3500 grams. You’ve reached your due date, and the baby is ready to arrive. About 10% of babies are born late. The baby is fully descended into the pelvis and ready for birth. Contractions are becoming stronger and more frequent. The mucus plug may dislodge, possibly with a small amount of bloody mucus. You may also experience a release of amniotic fluid, which can feel like involuntary urination. Regular contractions begin, signaling it’s time to contact your birthing center. Congratulations on your baby, and welcome to the newest member of the world!