Hct/Hb Ratio
Enter hematocrit (%) and hemoglobin to compare against the expected 3:1 ratio. Deviations may indicate lab inconsistencies or clinical conditions.
Hct/Hb ratio
3.00
Expected ratio
3.00
Deviation
+0.00
How to Use This Calculator
Input hematocrit and hemoglobin values
Use values drawn from the same complete blood count. Ensure hemoglobin unit matches the selected option.
Review the calculated ratio
The typical Hct/Hb ratio is approximately 3:1. Small deviations are common; large deviations merit evaluation.
Investigate significant discrepancies
Disproportionate values may signal lab errors, hemolysis, transfusion timing, dehydration, or abnormal RBC indices.
Formula
Hct/Hb ratio = Hematocrit (%) ÷ Hemoglobin (g/dL)
Expected ratio ≈ 3 (Hematocrit ≈ 3 × Hemoglobin)
Convert hemoglobin g/L → g/dL by dividing by 10
Full Description
The hematocrit-to-hemoglobin ratio is a simple cross-check for internal consistency of CBC results. Under normal conditions, hematocrit is roughly three times hemoglobin. Significant deviation may reflect measurement errors, abnormal RBC morphology, hemolysis, or fluid shifts. Use this ratio alongside MCV, RDW, and clinical context to detect discrepancies and guide further workup.
Frequently Asked Questions
Why is the expected ratio about 3?
RBCs occupy roughly three times the volume percentage compared with hemoglobin mass concentration in g/dL under typical conditions.
Can dehydration alter the ratio?
Yes. Hemoconcentration may raise hematocrit disproportionately, increasing the ratio above 3.
What about recent transfusions?
Lab draws soon after transfusion can show non-equilibrated values, causing mismatched Hct and Hb.
Is this ratio diagnostic?
No. It is a screening tool for consistency. Investigate abnormal ratios with repeat labs and clinical assessment.