Cardiac Index Calculator

What Is Cardiac Index?

Cardiac index (CI) normalizes cardiac output to body size. It helps compare pump function across patients of different stature. CI is commonly used in critical care and cardiology. Related tools: Max Heart Rate Calculator and Blood Pressure Calculator.

Formulas

$$\text{BSA (Haycock)} = 0.024265 \times h^{0.3964} \times w^{0.5378}$$

$$\text{Cardiac output} = \frac{SV \times HR}{1000}$$

$$\text{Cardiac index} = \frac{CO}{BSA}$$

Height $h$ is in centimeters, weight $w$ in kilograms, stroke volume (SV) in mL/beat, heart rate (HR) in beats per minute, and cardiac output (CO) in L/min. CI is reported in L/min/m².

Interpretation

• 2.5 to 4.0 L/min/m²: commonly considered normal
• Below 2.5: low cardiac index
• Below 2.0: range associated with cardiogenic shock