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Cardiac Output (CO) Calculator

Reviewed by George Lambroglou, RNLast updated 2 Jan 2026

Calculate cardiac output from stroke volume and heart rate for quick hemodynamic estimation.

Jump to:Calculator|How it works|Formula|Examples|Practice questions|FAQs|References

Commas allowed (e.g. 1,250).

Educational use only. Always interpret results in clinical context and verify with local policies/protocols.

How it works

Cardiac output (CO) is the volume of blood pumped by the heart each minute. A simple estimate is obtained by multiplying stroke volume (SV, the blood ejected per beat) by heart rate (HR, beats per minute).

This calculator assumes SV is entered in milliliters per beat and HR in beats per minute. The product gives mL/min, then dividing by 1000 converts the result to liters per minute (L/min).

Formula

CO (L/min) = (SV (mL) × HR (bpm)) ÷ 1000

Worked examples

Example 1: SV 70 mL and HR 75 bpm — calculate CO

CO = (SV × HR) ÷ 1000 CO = (70 × 75) ÷ 1000 CO = 5250 ÷ 1000 CO = 5.25 L/min
Answer: 5.25 L/min

Example 2: SV 50 mL and HR 110 bpm — calculate CO

CO = (50 × 110) ÷ 1000 CO = 5500 ÷ 1000 CO = 5.50 L/min
Answer: 5.50 L/min

Example 3: SV 30 mL and HR 130 bpm — calculate CO

CO = (30 × 130) ÷ 1000 CO = 3900 ÷ 1000 CO = 3.90 L/min
Answer: 3.90 L/min

Practice questions

Try it first, then reveal the answer and working.

Practice 1: SV 70 mL, HR 75 bpm. What is CO?

Show answer + workingHide
CO = (SV × HR) ÷ 1000
CO = (70 × 75) ÷ 1000
CO = 5250 ÷ 1000
CO = 5.25 L/min
Answer: 5.25 L/min

Practice 2: SV 50 mL, HR 110 bpm. What is CO?

Show answer + workingHide
CO = (50 × 110) ÷ 1000
CO = 5500 ÷ 1000
CO = 5.50 L/min
Answer: 5.50 L/min

Practice 3: SV 30 mL, HR 130 bpm. What is CO?

Show answer + workingHide
CO = (30 × 130) ÷ 1000
CO = 3900 ÷ 1000
CO = 3.90 L/min
Answer: 3.90 L/min

Clinical safety note: Cardiac output targets vary by patient and clinical context. A “normal” value does not guarantee adequate perfusion, and a low value may be appropriate in some settings. Use validated measurements and follow local protocols for shock/ICU management.

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Frequently asked questions

Clinical reminder: Always follow local protocols and consult medication information sheets. These examples are for calculation practice only.

References & Sources

These resources provide clinical context for cardiac output and hemodynamic monitoring.

Hemodynamics & shock

Vincent JL, De Backer D — Circulatory Shock

PubMed

N Engl J Med

High-quality overview of shock physiology and hemodynamic goals/assessment.

Surviving Sepsis Campaign Guidelines

Guideline

Society of Critical Care Medicine

Guideline recommendations for hemodynamic resuscitation targets and monitoring in sepsis.

Monitoring & measurement

Magder S — Invasive hemodynamic monitoring

PubMed

Critical Care Clinics

Review of invasive monitoring concepts relevant to CO interpretation and limitations.

Merck Manual Professional — Cardiac Output / Hemodynamics

Reference

Merck Manual Professional Edition

Clinician-focused reference on cardiac output concepts and clinical interpretation.

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