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Cardiac Index (CI) normalizes cardiac output to body size: CI = Cardiac Output / Body Surface Area. The commonly cited normal range is 2.5-4.0 L/min/m². This calculator is for general reference and educational purposes only — it is not a medical diagnosis. Consult a doctor for actual hemodynamic assessment.
How it works
Enter cardiac output (L/min) and body surface area (m²). The tool divides the two.
- Enter cardiac output (L/min).
- Enter body surface area (m²).
- Click Calculate to see your results.
Examples
Cardiac output 5 L/min, BSA 1.8 m²
CI = 5 / 1.8 = 2.78 L/min/m² — within the commonly cited normal range.
Who should use it
- Reviewing hemodynamic monitoring data alongside a doctor.
- Clinical and nursing education about cardiac performance metrics.
Industry applications
- Cardiology and critical care reference
- Clinical education
Advantages
- Accounts for body size, making it more comparable across patients than raw cardiac output.
- Simple, transparent division.
Limitations
- Requires an already-measured (often invasively obtained) cardiac output value.
- A single snapshot value — trends over time are more informative than one reading.
Common mistakes to avoid
- Using body weight-based formulas for BSA that differ from the one your care team uses, causing inconsistent results.
- Comparing cardiac index across measurements taken under very different physiological conditions (e.g. rest vs. exertion).
Best practices
- Use a body surface area figure calculated the same way each time (e.g. always the same formula) for consistent trending.
Tips
- Track cardiac index alongside other hemodynamic parameters, not in isolation, for a fuller picture.