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Hematocrit (HCT) Unit Converter
Hematocrit (HCT), also known as Packed Cell Volume (PCV), is a key component of the Complete Blood Count (CBC). It measures the volume percentage of red blood cells (RBCs) in a sample of whole blood. HCT is essential for evaluating the oxygen-carrying capacity of the blood.
HCT levels are closely related to Hemoglobin (Hgb) concentration (commonly approximated as HCT ≈ 3 × Hgb). Low HCT is the definition of Anemia, while high HCT (Polycythemia) can be caused by dehydration or excessive RBC production (polycythemia vera). Results are commonly reported as a percentage (%) or as a volume fraction (L/L).
SI Unit (Fraction)
RecommendedLiters of RBCs per liter of blood (e.g., 0.42).
Conventional Units
Clinical Context
Reference Ranges:
• Men: approximately 40% – 50% (0.40 – 0.50 L/L)
• Women: approximately 35% – 45% (0.35 – 0.45 L/L)
HCT is commonly used in estimating blood loss and monitoring hydration status. Dehydration artificially raises HCT due to decreased plasma volume, while overhydration lowers it. The relationship to Hemoglobin is often summarized as HCT ≈ 3 × Hgb (when Hgb is expressed in g/dL and HCT is expressed as a percentage).
Clinical References
How to Use This Calculator
Follow these steps to get accurate clinical conversions instantly.
Enter Values
Input your laboratory result into L/L (fraction, e.g. 0.42) or % (e.g. 42). You can use either dot or comma decimals.
Automatic Conversion
The calculator works in real time based on the simple relationship: Fraction × 100 = % = mL/100mL.
Verify Units
Remember that 1 L/L is numerically equal to 100% and to 100 mL/100mL.
Reset
Use the Clear button to reset all fields before starting a new calculation.
Frequently Asked Questions & Tips
Yes. mL of RBCs per 100 mL of whole blood is, by definition, a percentage (volume percent).
HCT is often calculated from the RBC count and Mean Corpuscular Volume (MCV) by automated analyzers, or measured directly by centrifugation in some settings.