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Hemoglobin (HGB) Unit Converter
Hemoglobin (Hgb) is the complex protein found inside red blood cells (RBCs) responsible for carrying oxygen from the lungs to tissues throughout the body. It consists of four subunits, each containing a heme group that binds iron. The concentration of hemoglobin is the most direct measure of the blood’s oxygen-carrying capacity.
Hgb measurement is a core component of the Complete Blood Count (CBC) and is used to diagnose Anemia (low Hgb) or Polycythemia (high Hgb). Hgb levels are typically interpreted alongside Hematocrit (HCT), as the volume of RBCs (HCT) should approximate three times the Hgb concentration (commonly summarized as Hct ≈ 3 × Hgb). Results are reported in grams per deciliter (g/dL) or grams per liter (g/L).
SI Units
RecommendedGrams per liter (g/L) or millimoles per liter (mmol/L).
Conventional Units
Clinical Context
Reference Ranges:
• Men: approximately 13.5 – 17.5 g/dL
• Women: approximately 12.0 – 15.5 g/dL
Anemia is typically defined as a concentration below the lower limit for the patient’s sex and age. Clinically, the relationship Hct ≈ 3 × Hgb is often used as a quick quality check for CBC results. The molar conversion relies on a molecular weight of 64,500 g/mol: 1 g/L ≈ 0.0155 mmol/L.
Clinical References
How to Use This Calculator
Follow these steps to get accurate clinical conversions instantly.
Enter Values
Input your laboratory result into the corresponding unit field (e.g., g/dL). You can use either dot or comma decimals.
Automatic Conversion
The calculator works in real time. As you type in one field, all other units (like g/L, mmol/L, mg/dL, and µg/mL) are instantly updated.
Verify Units
Check the SI Units section. Note that g/L is 10 times the numerical value of g/dL (for example, 15 g/dL = 150 g/L).
Reset
Use the Clear button to reset all fields before starting a new calculation.
Frequently Asked Questions & Tips
Yes. Grams per deciliter (g/dL) and grams percent (g%) are numerically identical.
Hemoglobin is a very large protein (molecular weight approximately 64,500 g/mol), so its concentration in moles per liter is tiny, and is usually expressed in mmol/L.