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Cardiac index calculator

Calculate cardiac index from cardiac output and Mosteller body surface area, or derive output from stroke volume and heart rate.

For feet, enter decimal feet: 5 ft 6 in is 5.5 ft.

Cardiac output
5
Mosteller body surface area (m²)
2.000
Cardiac index (L/min/m²)
2.500

Estimates for information only. Not financial, medical, legal or engineering advice. See the Terms.

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How this calculator works

Cardiac index normalizes cardiac output to body surface area. This page uses the Mosteller equation, with height in centimetres and mass in kilograms. Output mode accepts a measured cardiac output; stroke-volume mode multiplies volume per beat by beats per minute. A calculated index does not diagnose the cause of abnormal circulation. The result is an estimate for information only and is not medical advice.

Formula

BSA(m²) = √[height(cm) × weight(kg) / 3600]. CO(L/min) = SV(mL/beat) × HR / 1000. CI = CO / BSA.

Worked example

At height 180 cm and weight 80 kg, BSA is 2 m². An output of 5 L/min gives CI 2.5 L/min/m²; 80 mL at 75 beats/min gives output 6 and CI 3.

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Frequently asked questions

Which surface area equation is used?

Mosteller. Another laboratory formula may give a slightly different index.

Can I enter output in L/s?

Yes. The flow unit selector converts it before indexing.

Is cardiac index the same as ejection fraction?

No. Index describes flow per surface area; ejection fraction describes the fraction of filled ventricular volume ejected.

Sources

Written byAmira MansourCalculator writer. Builds and tests Mathulate calculators against published sources.
Reviewed byPriya Natarajan, RDRegistered dietitian. Checks health calculators against public health guidance.

Last updated .

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