# Cardiac Index Calculator (CI) Compute CI = CO / BSA with BSA from the Mosteller formula √(height × weight / 3600). Normal 2.5–4.0 L/min/m². Derived from Mosteller NEJM 1987, Du Bois 1916, StatPearls, LITFL. Not medical advice. > Canonical page: https://elysiatools.com/en/tools/cardiac-index-calculator - **Category:** Health - **Keywords:** cardiac index, ci, cardiac output index, body surface area, bsa, mosteller, indexed cardiac output, hemodynamics, heart failure, shock, cardiology, critical care ## Overview The Cardiac Index Calculator computes cardiac index (CI) in L/min/m² from cardiac output, height, and weight. It calculates body surface area (BSA) with the Mosteller formula and compares the result with the stated normal range of 2.5–4.0 L/min/m². This tool is for informational use and is not medical advice. ## Inputs - **Cardiac Output CO (L/min)** (number): Cardiac output in L/min (from thermodilution, Fick, or echo). - **Height (cm)** (number): Patient height in centimeters, used to compute BSA via Mosteller. - **Weight (kg)** (number): Patient weight in kilograms, used to compute BSA via Mosteller. - **Decimal Places** (number) ## When to use - Estimate cardiac index when cardiac output, height, and weight are available. - Normalize cardiac output for body size when reviewing hemodynamic measurements. - Check whether a calculated CI falls within the listed normal range of 2.5–4.0 L/min/m². ## How it works - Enter cardiac output in L/min, height in centimeters, and weight in kilograms. - The calculator computes BSA using √(height × weight / 3600), the Mosteller formula. - It divides cardiac output by BSA using CI = CO / BSA. - The JSON result includes BSA, cardiac index, category, calculation method, and model information. ## Use cases - Cardiology review of cardiac output adjusted for patient body size. - Critical care documentation of calculated hemodynamic values. - Educational practice with the Mosteller BSA and cardiac index formulas. ## Frequently asked questions ### What is the cardiac index formula? Cardiac index is calculated as CI = cardiac output (CO) / body surface area (BSA). ### How is BSA calculated? BSA is calculated with the Mosteller formula: √(height in cm × weight in kg / 3600). ### What inputs are required? Enter cardiac output in L/min, height in cm, and weight in kg. Decimal places are optional. ### What is the normal cardiac index range? The stated normal range is 2.5–4.0 L/min/m². ### What does the calculator return? It returns a JSON result containing BSA, cardiac index, a category, the method, and model information. ## Related tools - [A-a Gradient (Alveolar-Arterial O₂)](https://elysiatools.com/en/tools/a-a-gradient-calculator): Calculate the alveolar-arterial O₂ gradient to distinguish hypoxemia causes. PAO₂ = FiO₂×(P_atm−47) − PaCO₂/0.8; A-a = PAO₂ − PaO₂. Normal ≈ (Age+10)/4. Elevated → V/Q mismatch, shunt, diffusion impairment. Derived from StatPearls, LITFL, Cornell PICU, and Martin 1999. 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