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Beta hCG doubling time
Calculate hCG doubling time from two quantitative lab results and see a simple chart of the trend.
Estimate, not a diagnosis. This tool gives an educational estimate based on the numbers you enter. It cannot account for your individual health history — consult a healthcare professional for anything clinical.
How this works
Using two hCG values and their dates, we estimate the exponential growth rate and report the doubling time in days. Early pregnancy typically shows roughly doubling every 48–72 hours, but values vary.
Limitations
Assay differences, lab error, and biological variation affect results. This is an aid, not a diagnosis — discuss abnormal patterns with your clinician.
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Frequently asked questions
What is a normal hCG doubling time in early pregnancy?
Roughly every 48 to 72 hours in early pregnancy, though the rate slows as hCG levels get higher. This calculator works out your actual doubling time from two lab values and their dates.
Is a slower doubling time always a problem?
Not necessarily — doubling time naturally slows as absolute hCG levels rise, and there is real variation between healthy pregnancies. A pattern well outside the expected range is worth discussing with a clinician, not a single data point.
Why do two labs give different hCG numbers for a similar timeframe?
Different assays and lab methods can produce somewhat different absolute numbers. Comparing values from the same lab over time is more reliable than comparing across different labs.