hCG calculator
Beta-hCG is the hormone a pregnancy test detects, and in early pregnancy its level normally rises in a predictable way — doubling roughly every 48 to 72 hours. Rather than any single number, it's this rate of rise that providers watch as a reassuring sign in the first weeks. Enter two beta-hCG results and the hours between the blood draws below to see your doubling time and percent rise, and how they compare to the typical early-pregnancy range.
Enter both hCG values and the hours between draws.
How to read your hCG result
In early pregnancy, beta-hCG normally rises quickly — doubling about every 48 to 72 hours. Because a single value tells you little on its own, providers look at the rate of change between two blood draws. As a general benchmark, a rise of at least 53% over 48 hours is considered consistent with a potentially viable pregnancy (ACOG; РОАГ). A rise slower than that warrants follow-up but doesn't by itself confirm a problem.
This pattern only holds early on. Once hCG climbs above roughly 1,200–6,000 mIU/mL, doubling naturally slows down, so a longer doubling time at higher levels is expected and not a cause for concern. Numbers also vary widely between healthy pregnancies, which is why ranges by week are broad. A doubling-time calculator describes the trend; it cannot diagnose a viable, ectopic, or failing pregnancy. Only your healthcare provider can interpret hCG alongside your dates and an ultrasound. This tool is for general information and is not medical advice.
Common questions
In early pregnancy, hCG typically doubles roughly every 48 to 72 hours. A rise of at least 53% over 48 hours is generally considered consistent with a potentially viable pregnancy, but your provider interprets it alongside your other results.
Levels vary enormously between healthy pregnancies, so the ranges are wide: very roughly, 5–50 mIU/mL around 3 weeks, into the hundreds by week 4, and the thousands to tens of thousands by weeks 5–6. Because a single number means little on its own, the trend over time matters far more than where you fall in these broad bands.
Doubling times of about 48 to 72 hours are common in the first weeks. As hCG rises above roughly 1,200–6,000 mIU/mL, doubling naturally slows — so a longer doubling time at higher levels is expected, not a red flag.
A slower-than-expected rise can have several explanations and does not by itself confirm a problem, especially once levels are already high. Your provider will repeat the test and add an ultrasound to interpret the trend. Falling or plateauing levels need prompt review, so contact your provider with your results.
Higher-than-average hCG can occur with twins, but it cannot confirm them — single pregnancies span a wide range too, and levels overlap heavily. Only an ultrasound can diagnose a multiple pregnancy. Treat a high reading as a question for your provider, not an answer.
No. It is an educational tool that describes a trend, not a diagnosis. It cannot distinguish a viable, ectopic, or failing pregnancy. Always confirm your hCG results and their meaning with your healthcare provider.
Medical Disclaimer
This article is for informational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or qualified health provider with any questions you may have regarding a medical condition.
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