hCG Levels Calculator

hCG reference ranges

hCG rises from near-zero at conception to a peak of 25,000–290,000 mIU/mL around weeks 8–12, then gradually falls and stabilises through the second and third trimesters. The ranges are very wide — individual variation is substantial even in normal pregnancies.

A value outside the typical range for a given gestational age does not necessarily indicate a problem. Multiple pregnancies (twins, triplets) often produce higher hCG values, and some normally-progressing pregnancies produce values at the low end of the range.

Doubling time

In a normally progressing pregnancy, hCG typically doubles every 48–72 hours in the first few weeks. A doubling time below 48 hours is considered normal; above 72 hours may prompt further investigation, though it is not always abnormal.