hCG Calculator

Home > Calculators >beta hCG calculator

Beta hCG Doubling Time Calculator

You can use the calculator below to calculate the doubling time of two beta hCG samples by entering the date of the blood test and the corresponding beta hCG value for that day. If the hCG level is decreasing the the half life  will be calculated.

To calculate the doubling time of two beta hCG samples:
1. Enter the date the first blood test was drawn and the beta HCG value for the date the sample was drawn
2. Enter the date the second blood test was drawn and the beta HCG value for the date the sample was drawn.

Date blood sample drawn HCG level
Date of first beta hCG
First beta value
Date of second  beta hCG
Second beta value


Beta hCG levels usually double about every 2 days for the first four weeks of pregnancy.  As  pregnancy progresses the doubling time becomes longer. By 6 to 7 weeks beta hCG levels may take as long as 3 1/2 days to double . hCG normally reaches a peak level at about 8 to 10 weeks and then declines for the remainder of the pregnancy.

Morse and coworkers (2012) at University of Pennsylvania School of Medicine recommend that the beta hCG level for a successful intrauterine pregnancy should be expected to increase by at least 35% in two days.  A slower rate of increase suggests a possible miscarriage or ectopic pregnancy.  For women who are having a miscarriage the beta hCG should be expected to fall 36 - 47% over two days. A fall that  is slower than this is suggestive of an ectopic pregnancy.

About 21% of ectopic pregnancies (pregnancies implanted outside of the uterus)  have a rise in hCG similar to an intrauterine pregnancy and 8% of ectopic pregnancies  have a fall in hCG similar to a miscarriage.

Serial hCG values should not be used alone to determine whether or not  a pregnancy is  likely to be a successful intrauterine pregnancy, a miscarriage, or an ectopic pregnancy.  Serial hCG values
should be used in combination with clinical judgment, evaluation of symptoms and repeat ultrasound (as needed).

Reference Ranges for beta hCG (using the Roche Cobas analyzer) during the first half of pregnancy are shown below

Week of Gestation Beta Human Chorionic Gonaotropin (mIU/mL)
3 6 - 71
4 10 - 750
5 217 - 7138
6 158 - 31795
7 3697 - 163563
8 32065 - 149571
9 63803 - 151410
10 46509 - 186977
12 27832 - 210612
14 13950 - 62530
15 12039 - 70971
16 9040 - 56451
17 8175 - 55868
18 8099 - 58176

1. Ashitaka Y et al. Production and secretion of hCG andhCG subunits by trophoblastic tissue. In Segal S (ed):Chorionic Gonadotropins. New York, Plenum, 1980 p 151.
2. Pittawy DE et al. Doubling times of human chorionic gonadotropin increase in early viable intrauterine pregnancies. Am J Obstet Gynecol 1985; 299-302. PMID:2408475
3. American College of Obstetricians and Gynecologists. Medical Management of Tubal Pregnancy. Practice Bulletin Number 3, December 1998. Washington, D.C. ACOG, 1998
4. Barnhart KT, et. al.,Symptomatic patients with an early viable intrauterine pregnancy: HCG curves redefined. Obstet Gynecol. 2004 Jul;104(1):50-5.PMID:15229000
5.Barnhart KT, et. al. . Decline of serum hCG and spontaneous complete abortion: defining the normal curve. Obstet Gynecol 2004; 104:97581 PMID:15516387
6. Seeber BE, Barnhart KT. Suspected ectopic pregnancy. Obstet Gynecol. 2006 Feb;107(2 Pt 1):399-413. PMID:16449130
7.Morse CB, et. Al., Performance of human chorionic gonadotropin curves in women at risk for ectopic pregnancy: exceptions to the rules. Fertil Steril. 2012 Jan;97(1):101-6.e2. PMID:22192138
8. Silva C, et al.,  Human chorionic gonadotropin profile for women with ectopic pregnancy. Obstet Gynecol. 2006;107(3):60510 PMID:16507931
9. Human Chorionic Gonadotropin (hCG) on Elecsys 1010/2010 and Modular Analytics E170 [package insert 2007-2009, VII] Indianapolis,Ind;Roche

All calculations must be confirmed before use. The suggested results are not a substitute for clinical judgment. Neither nor any other party involved in the preparation or publication of this site shall be liable for any special, consequential, or exemplary damages resulting in whole or part from any user's use of or reliance upon this material.

Home | About | Disclaimer | Privacy | Contact | Sitemap