hCG Levels Calculator

Created by Bogna Szyk and Kacper Pawlik
Last updated: Aug 01, 2021

This hCG levels calculator is a tool for assessing whether an early-stage pregnancy is developing properly. It take the results of two hCG tests, as 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.

If you or your significant other is pregnant, make sure to take a look at the pregnancy weight gain calculator too!

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, 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 the 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 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 mlU/ml, ectopic pregnancy is highly probable. Moreover, a lack of growth or a drop of 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. To calculate the risk of developing a specific type of human carcinoma - take a look at our lung cancer risk calculator!

How to use the hCG doubling calculator

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

  • First hCG level (hCG₁). This is the result of the first hCG test that you took. It is measured in mIU/ml. (IU - International Unit, 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). Similarly, this is the result of the second hCG test, taken after some time, at least a few days.
  • Time between measurements (T). The number of hours that have 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 difference. 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 (T₂). The average number of hours required for your hCG levels to double. This value is calculated according to the following formula:

    T₂ = T / log₂ (hCG₂/hCG₁)

  • 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 = [2 ^(24/T₂) - 1] * 100%

  • Two day increase. Analogically to the one day increase, this measures the relative increase of hCG over two days.

    I₂ = [2 ^(48/T₂) - 1] * 100%

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 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.

pregnancy weekhCG levels in blood (mIU/ml)
Men and non-pregnant women <5
1 week 5-50
2 weeks 50-500
3 weeks 100-10,000
4 weeks 1080-30,000
6-8 weeks 3500-115,000
12 weeks 12,000-270,000
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 the 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 urine of a pregnant woman (which, as we already know, contains hCG) into a Xenopus toad caused the toad to ovulate. Needless to say, that before researchers fully understood the processes behind this phenomena, the poor Xenophus 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 womans 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 instruction included by the producer of the testing set before taking the test to assure its effectiveness. The result appears typically after several (5 to 10) minutes.

Pregnancy test

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

The advantage of a hCG blood tests is their ability to measuring the change of hCG concentration in 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 and ovulation calculators!

Trying to prevent pregnancy? You may check whether you may really trust your birth control method.

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.

Are you dreaming about losing some pounds? Why not take an Omni Calculator weight loss trip! We have solutions that will help you at each step of your weight loss plan. First, you can check how much fat your body has using the body fat or body adiposity index calculators. Then you can calculate how many calories your meals should contain each day with our calorie calculator, so you lose weight in a healthy way. Finally, we can keep you motivated in whatever sport you play with the burned calories calculator! You don't need the hCG diet at all!

Bogna Szyk and Kacper Pawlik
First β-hCG level
Second β-hCG level
Time between measurements
Percentage difference
Doubling time
One day increase
Two day increase
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