hCG Tracking Tool
Input your serum hCG value to see how it compares with expected pregnancy ranges. Add sequential results to calculate doubling time.
Optional: calculate doubling time
Doubling time is most informative when samples are 48 hours apart during early pregnancy (<6 weeks).
How to Use This Calculator
Select gestational reference
Use either gestational age (weeks/days) or estimated days post ovulation depending on your available data.
Enter serum hCG values
Compare your result with population reference ranges for ongoing pregnancies.
Track trends over time
Input serial values with timestamps to estimate doubling time and discuss patterns with your provider.
Formula
Doubling time (hours) = Δt × ln(2) ÷ ln(hCG₂ ÷ hCG₁)
Gestational reference = convert gestational weeks/days or DPO to weeks for comparison
Percentile estimate = linear interpolation between reference minimum and maximum
Full Description
Serum hCG rises rapidly in early pregnancy, doubling approximately every 48–72 hours through the first six weeks, plateauing near 10 weeks, then declining to lower steady levels. Individual values vary widely; trends are more informative than single measurements. Extremely high or low values may signal multiples, molar pregnancy, or potential miscarriage/ectopic pregnancy, necessitating clinician follow-up. This tool references commonly cited hCG ranges but does not replace medical interpretation.
Frequently Asked Questions
Is one high value enough to confirm a healthy pregnancy?
No. hCG trends and ultrasound confirmation are essential for assessing viability.
Do multiples always produce higher hCG?
Multiples often have higher values, but ranges overlap. Ultrasound is needed for definitive diagnosis.
What if my levels drop?
A falling hCG in early pregnancy usually signals miscarriage or ectopic pregnancy. Seek immediate medical advice.
Can medications affect hCG?
Yes. Fertility medications containing hCG can raise levels temporarily. Inform your clinician about recent injections.