Cardiac Output Calculator

The Cardiac Output Calculator estimates cardiac output and cardiac index based on stroke volume, heart rate, and body surface area. This tool helps medical professionals and patients assess heart function and blood circulation efficiency. Whether you are evaluating cardiovascular health, monitoring a critically ill patient, or checking fitness levels, this calculator provides immediate, reliable results for better health decisions.

Amount of blood pumped by the heart in one beat (milliliters)
Number of heart beats per minute (bpm)
Patient's body surface area (m²) - optional for cardiac index calculation

How Cardiac Output Is Calculated

Cardiac Output measures the volume of blood the heart pumps every minute, indicating how well the heart meets the body's metabolic needs. The standard calculation uses two key values to determine this flow rate.

Cardiac Output = Stroke Volume × Heart Rate

Where:

  • Stroke Volume = Amount of blood ejected per beat (mL)
  • Heart Rate = Number of beats per minute (bpm)

First, the calculator multiplies the stroke volume by the heart rate to find the total blood flow in milliliters per minute. This step is crucial because it combines the strength of each beat with the speed of the heart. If you provide a body surface area, the tool then divides the output by this area to calculate the Cardiac Index.

This method provides a standardized way to evaluate heart performance across different body sizes.

What Your Cardiac Output Means

This number represents the total amount of blood your heart moves through your body in one minute. Understanding your result helps you gauge if your heart is pumping effectively to meet your body's demands.

Result Interpretations

  • Normal Resting Adult: A range of 4 to 8 L/min generally indicates a healthy heart function at rest.
  • During Exercise: Values can rise significantly, often reaching 20 to 30 L/min in athletes, showing strong cardiovascular response.
  • Low Output: Readings below 4 L/min may suggest the heart is not pumping enough blood, potentially indicating shock or heart failure.

Important Note

Because cardiac output varies by body size, always consider the Cardiac Index (L/min/m²) for a more accurate comparison between individuals. A normal Cardiac Index typically falls between 2.5 and 4.2 L/min/m².

This calculator is for informational purposes only and is not intended as a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition.

Monitor your values regularly to track how lifestyle changes or medications affect your cardiovascular health over time.

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