Cardiac Output Calculator

Written by Great Medico

Updated September 24, 2026 •3 min read

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Cardiovascular numbers become useful only when the equation behind them is clear. Cardiac Output Calculator turns the specific measurements in this tool into a focused hemodynamic or risk estimate.

What this calculator does

Cardiac Output Calculator uses Your height, Your weight, Body surface area, O₂ consumption, Hemoglobin, Arterial oxygen saturation, Arterial oxygen tension, and the remaining fields shown to calculate cardiac output and cardiac index. It is built around the exact fields displayed in this plugin rather than a generic version of the topic. Where supported, it also shows Body surface area, O₂ consumption, and Arterial O₂ concentration so the primary result is easier to place in context. Cardiovascular formulas are sensitive to measurement technique and clinical context. A mathematically correct output can still be misleading if the input was obtained under a different physiologic condition, with a different assay, or outside the population for which the score was developed.

How to use it

Complete the requested fields, including Your height, Your weight, Body surface area, O₂ consumption, Hemoglobin, and Arterial oxygen saturation, then finish the remaining items shown in the calculator. Confirm that each yes/no, category, date, or score option is applied exactly as labeled. When the formula combines measurements, use values obtained under the same assessment or physiologic conditions whenever possible.

How the calculation works

The engine uses the Fick principle. If body surface area is not supplied, it estimates BSA from height and weight with the Mosteller equation; if oxygen consumption is missing, it uses 125 mL/min per square meter. Arterial and venous oxygen content are calculated from hemoglobin, oxygen saturation, and oxygen tension, and cardiac output equals oxygen consumption divided by the arterial–venous oxygen-content difference. Cardiac index is cardiac output divided by BSA.

Example

Using the sample values prefilled in this calculator, the primary result is 5.369 L/min (Cardiac output), Body surface area is 1.9 m², and O₂ consumption is 240 mL/min. This worked example shows how the plugin’s own default inputs flow through the implemented method; replace them with the correct patient, laboratory, imaging, or personal values before interpreting a result.

How to interpret the result

Read the output as cardiac output generated by this specific formula or score. The number is most useful when compared with the clinical context and, when appropriate, serial measurements or the current guideline pathway for the condition. A boundary value should not be overinterpreted as a sudden change in physiology.

Limitations and notes

The Fick estimate is sensitive to measured oxygen consumption, hemoglobin, saturation sampling, and whether arterial and true mixed-venous blood were obtained correctly. Assumed VO₂ can introduce substantial error. The result is a hemodynamic estimate and should be interpreted with the patient’s clinical state, not as a stand-alone diagnosis.