When a woman misses a period and suspects she is pregnant, taking a urine pregnancy test at home is often the first step. This test measures an important hormone in the urine called human chorionic gonadotropin (hCG). The hCG calculator is a tool that is primarily used during the early stages of one's pregnancy. It is used to assess whether the pregnancy is developing appropriately. The hCG Levels Calculator determines a parameter known as Doubling Time (DT). It is the time taken for the value of hCG in your blood/urine to double. There is a standard reference available to which your Doubling Time is compared, and if it differs from normal, it can be an important diagnostic indicator of something abnormal.
Commonly referred to as the pregnancy hormone, hCG is secreted by a specific group of cells that are present around the developing embryo called syncytiotrophoblasts. These are the cells that go on to form the placenta. hCG interacts with the ovary and enables it to produce a hormone called progesterone. Progesterone is very important to ensure the continuation of the pregnancy. It prevents the uterus from contracting prematurely and increases the blood supply to the inner lining layer of the uterus, which ensures the developing embryo gets adequate nutrition.
hCG monitoring helps your doctor check whether the pregnancy is progressing normally or not. If the values are abnormally elevated, then it can be indicative of the following.
Twin pregnancy (multiple pregnancy)
Ectopic pregnancy (a condition where the fertilised egg implants at a site outside the uterus)
Molar pregnancy (a condition where a non-viable fertilised egg implants in the uterus resulting in an abnormal growth; also called hydatidiform mole)
Specific kinds of growths & tumours (germ cell tumour/trophoblastic tumour)
hCG is measured in the following ways; qualitatively (which detects the presence of hCG) and quantitatively (where the amount of hormone is measured).
Qualitative hCG test is the commonly used urine pregnancy test, which detects the presence of hCG in urine. It, however, cannot estimate the concentration.
Quantitative hCG testing is done from a blood sample. Called a beta-hCG test, the levels in the blood can be measured around 11-12 days following conception. The measured value of hCG is expressed in the units milli-IU per mL.
Below is a reference table for expected hCG values in pregnancy. Note that this is not a substitute for a doctor's opinion because your situation can be unique and can only be confirmed by clinical examination and analysing these findings along with scan reports and other blood work.
Weeks since LMP
hCG Reference Range (in milli-IU/mL)
5 - 50
5 – 428
18 – 7,340
1,080 – 56,500
7,650 – 229,000
25,700 – 288,000
13,300 – 254,000
4,060 – 165,400
3,640 – 117,000
Non-pregnant women & men
LMP stands for Last Menstrual Period and is the first date on which your last period before pregnancy started, and the term refers to crossing 37 weeks in pregnancy, by which time the baby is fully developed and can be delivered.
A hCG value of 5 milli-IU/mL is diagnostic of pregnancy. Anything below that is considered a negative pregnancy test. hCG values alone are not used to confirm the pregnancy. Your doctor will perform/ order an ultrasound scan to confirm the findings and date the pregnancy.
Once a pregnancy is confirmed, hCG levels may be monitored at every visit, especially if the mother has had a history of previous pregnancy loss/ ectopic pregnancy/ molar pregnancy. It is not routinely done for every pregnant woman. Your doctor will make the decision based on your clinical history and pregnancy status.
Using an hCG calculator is very simple. You have to enter the dates on which the beta hCG levels were checked and the values on each date. The calculator will generate the doubling time.
hCG levels vary widely in women during pregnancy. Typically, the levels of hCG in blood & urine double every 24 hours during the first 8 weeks of pregnancy. It reaches a peak at around 10 weeks, after which they plateau and fall till the 16th week. Following this, they remain fairly consistent in value till the end of pregnancy.
To calculate DT, you need three values:
hCG1: the first hCG value that was measured
hCG2: the second hCG test value, typically taken after a few days
T: time between the two tests expressed in days
The doubling time of hCG is very short during the initial weeks. As hCG values rise, the doubling rate decreases. You can expect the following doubling times.
hCG under 1200 milli-IU/mL: between 30-72 hours
hCG between 1200-6000 milli-IU/mL: between 72-96 hours
hCG more than 6000 milli-IU/mL: over 96 hours.
It is important to note that all of these values do not replace the opinion of your treating doctor. This is meant only as a reference/ guide. Remember that hCG values can often have a wide range of variation between different people. If you encounter an abnormal value, then make sure to consult your doctor immediately so that they can verify the status and condition of the pregnancy.
As there are several reasons for the beta hCG hormone to be present in the blood, it is not diagnostic of pregnancy. An ultrasonography showing a viable foetus (with a heartbeat at around 6-7 weeks) is confirmatory.
A normal pregnancy, a miscarriage, and an ectopic pregnancy can all have similar patterns in the rise or fall of beta hCG levels. Hence the doubling time alone should never be used for diagnosis. Only a trained medical professional can give you a diagnosis after appropriate examination and testing.
Disclaimer: The content on this page is generic and shared only for informational and explanatory purposes. Please consult a doctor before making any health-related decisions.