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hCG Levels Calculator

Table of contents

What is hCG?What are hCG levels?How to use the hCG doubling calculatorNormal doubling timeshCG level charthCG pregnancy testhCG dietFAQs

This hCG levels calculator is a tool for assessing whether an early-stage pregnancy is developing properly. It takes the results of two hCG tests and uses them to determine the hCG doubling time, as well as the one- and two-day increase of this hormone. In this article, we will explain what hCG is, what hCG levels mean, and how to use the hCG doubling calculator. You will also learn the story of the hCG pregnancy test and why taking the hCG diet is a bad idea. Finally, we will provide you with an hCG level chart that will help you interpret your results.

What is hCG?

hCG, or Human Chorionic Gonadotropin, is a hormone produced by the placenta during pregnancy. hCG interacts with the luteinizing hormone/choriogonadotropin receptor (LHCGR) of the ovary and, through this process, stimulates the corpus luteum — the remains of an ovarian follicle that has already released an ovum. Thanks to this stimulation, the corpus luteum produces the hormone progesterone until the moment the placenta is mature enough to begin and sustain progesterone synthesis by itself. Progesterone, in turn, has an influence on the uterus; it prevents it from contracting and, furthermore, maintains the secretory uterine lining, providing a constant supply of nutrients to the fetus. These effects ensure that pregnancy may develop physiologically without any problems.

What are hCG levels?

Extremely high levels of hCG can indicate a multiple pregnancy (for example, twins). On the other hand, low hCG levels may indicate an ectopic pregnancy. This means that the fertilized egg has been implanted in a place other than the uterus. When there is no visible fetus on a vaginal USG combined with a hCG of over 1500 mIU/ml, ectopic pregnancy is highly probable. Moreover, a lack of growth or a drop in hCG levels may suggest a miscarriage.

Apart from pregnancy, high hCG levels are characteristic of cancer of the ovaries or testicles. Both of these conditions cause this hormone to be released into the body.

How to use the hCG doubling calculator

You need to input the following three values into the hCG calculator:

  • First hCG level (hCG1\text{hCG}_1). This is the result of the first hCG test that you took. It is measured in mIU/ml. IU — International Unit is a unit used to measure an amount (mass or volume) of a certain substance based on its biological activity or effect.
  • Second hCG level (hCG2\text{hCG}_2). Similarly, this is the result of the second hCG test, taken after some time, at least a few days.
  • Time between measurements (TT). The time that has passed between the first and the second measurement.

Once you have provided our hCG levels calculator with these values, it will automatically calculate all of the remaining numbers.

  • Difference. This is simply the first hCG level subtracted from the second hCG level. The result should be positive; if not, it means that your hCG levels are falling.
  • Percentage change. Found as the difference between the two hCG levels divided by the result of the first measurement, this value shows you the relative increase that has occurred between the two measurements.
  • Doubling time (T2T_2). The average number of hours required for your hCG levels to double. This value is calculated according to the following formula:
T2=T/log2(hCG2hCG1)\qquad T_2 = T / \log_2\left(\frac{\text{hCG}_2}{\text{hCG}_1}\right)
  • One day increase. It is the percentage increase of your hCG levels over a 24-hour period. To find it, simply apply the equation below:
I1=100(2(24/T2)1)\qquad I_1 = 100\cdot(2^{(24/T_2)} - 1)
  • Two day increase. Analogical to the one-day increase, this measures the relative increase of hCG over two days.
I2=100(2(48/T2)1)\qquad I_2 = 100\cdot(2^{(48/T_2)} - 1)

Normal doubling times

As a rule, hCG levels increase only for the first 14–16 weeks of your pregnancy. After a peak in the fourteenth week, the hCG results begin to gradually drop. Soon after delivery, the hCG levels go back to their regular pre-pregnancy value.

The doubling times of hCG are very short at the beginning of pregnancy, and the rate decreases as the hCG level increases. You can expect the following doubling times:

  • hCG under 1,200 mIU/ml: between 30 and 72 hours.
  • hCG between 1200–6000 mIU/ml: between 72 and 96 hours.
  • hCG over 6,000 mIU/ml: over 96 hours.

Do you remember your due date? You can calculate it using our due date calculator.

hCG level chart

Remember that the "regular" values provided below are just a guide and are not equivalent to a doctor's consultation! In case of doubts, make sure to schedule an appointment! After the baby is born, doctors will assess it with another chart called the APGAR scale. You can visit our APGAR score calculator to learn more on this topic.

Week of pregnancy

hCG levels in blood (mIU/ml)

Men and non-pregnant women


1 week


2 weeks


3 weeks


4 weeks


6–8 weeks


12 weeks


13–16 weeks

Up to 200,000

hCG pregnancy test

hCG is a very reliable marker to indicate that someone is pregnant. It can already be detected in the blood eight days after the fertilization of the egg, and ten days for urine. Although the hCG marker is very sensitive, you have to keep in mind that if the test occurs during these 8–10 days after fertilization, it could give a falsely negative result. It means that in spite of the presence of a developing pregnancy inside a woman's body, the pregnancy test may come back negative.

Hillel Shapiro and Harry Zwarenstein developed the first version of the hCG pregnancy test at the beginning of the 1930s. They discovered that injecting the urine of a pregnant woman (which, as we already know, contains hCG) into a Xenopus toad caused the toad to ovulate. Needless to say, before researchers fully understood the processes behind this phenomenon, the poor Xenopus toads were massively exported and used as a pregnancy test.

The most popular hCG pregnancy test for at-home use is the one requiring a sample of the woman's urine. A woman either has to urinate into a plastic cup and then place a small amount of urine on a testing stick using a dropper or urinate directly on a testing stick, depending on the producer. It is crucial to carefully read the instructions included by the producer of the testing set before taking the test to ensure its effectiveness. The result typically appears after several (5 to 10) minutes.

Pregnancy test
By Ceridwen — Own work, CC BY-SA 2.0 fr, Wikipedia

The advantage of hCG blood tests is their ability to measure the change in hCG concentration over time. This way, we can indirectly verify that the fetus is developing correctly, which is where our hCG levels calculator comes in handy.

Do you plan on becoming a mother? You can calculate the times of your periods and ovulation with our period calculator and ovulation calculator!

hCG diet

The hCG diet is an example of someone making a false conclusion after clinical studies. The idea of adding hCG injections to a diet plan was created by Albert T. W. Simeons after his research on pregnant women in India. He reported that patients on a calorie-deficient diet lost mostly fat tissue and not muscle mass. Therefore, he designed a dietary protocol of low-dose daily hCG injections combined with extremely low-calorie intake — less than 500 calories per day.

However, many later performed studies on the hCG diet did not find the same results. The effect of the weight loss can be attributed entirely to such a low supply of calories (it is recommended for a normal adult to consume around 2000–2500 calories per day), while hCG injections can lead to many undesired side effects, including depression, irritability, fatigue, edemas, swelling of the men's breasts, and the formation of blood clots that can block blood vessels, potentially leading to heart attacks or strokes. The Food and Drug Administration (FDA) did not approve hCG for OTC (over-the-counter) use and obliged the producers of hCG medications to put a label on their products, noting that hCG is not effective for weight loss.


How do I calculate hCG levels at home?

You cannot calculate your hCG levels without the blood tests, so you cannot do it on your own at home. However, if you already have your results, you can calculate doubling time (DT) on your own. Use the following formula:

DT = T /(log2(hCG2/hCG1))


  • T — Time between measurements (hours);
  • hCG1 — First hCG measurements; and
  • hCG2 — Second measurement.

How can I tell if my hCG levels are rising?

The only safe method to tell if your hCG levels are rising is getting a blood test. Symptoms such as nausea, bloating, spotting, or breast soreness can occur due to an increasing hCG level. Still, you can't use them to estimate the hCG level from day to day.

How do I calculate pregnancy week if my hCG is 10,800?

You can be between 4 and 8 weeks pregnant. To calculate your pregnancy progress with hCG levels, you can use the hCG levels chart.

What are hCG levels while pregnant with twins?

While pregnant with twins, your hCG levels can be on the higher end of the standard hCG range. The levels shouldn't permanently exceed the range, though. It doesn't mean that high hCG levels always indicate twins — twins can only be confirmed with an ultrasound examination.

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