🧪 hCG Levels Calculator
Compare two hCG blood test results to calculate the percent increase and the doubling time between them.
What hCG levels indicate
Human chorionic gonadotropin (hCG) is a hormone produced during early pregnancy. In a typical early pregnancy, hCG rises quickly, and healthcare providers sometimes order two blood tests a day or two apart to check that the level is rising at an expected pace.
How this calculator works
Enter your two hCG test results and the number of hours between the tests. The calculator finds the percent change between the two readings and estimates the doubling time using the standard exponential growth formula: doubling time equals the elapsed hours multiplied by the natural log of 2, divided by the natural log of the ratio between the two values.
For hCG levels below roughly 1200 mIU/mL, a doubling time of about 48 to 72 hours is generally considered a normal early pregnancy pattern, though rises naturally slow as levels climb higher. Many factors affect individual results, so this calculator is for general educational purposes only and any concerns about your results should be discussed with your healthcare provider.