Cardiac Output Explained
How much blood the heart moves each minute and why it matters.
The formula
Cardiac output equals heart rate times stroke volume. A typical resting adult pumps about 5 litres per minute.
Cardiac index
Dividing by body surface area gives the cardiac index, so people of different sizes can be compared. Normal is 2.5 to 4.0 L/min/m².
In the body
Fitness raises stroke volume so the heart does the same work with fewer beats. Low output can cause fatigue and breathlessness and needs medical review.
Try it: Cardiac Output Calculator
Example with sample values. Open the full calculator →
Cardiac output4.9 L/min
Cardiac index2.7 L/min/m²
BSA1.82 m²
Normal resting cardiac output is 4–8 L/min and cardiac index 2.5–4.0 L/min/m².
Educational content only. This article does not replace advice from a qualified health professional. Medical disclaimer.