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Stroke Volume Calculator

Calculate stroke volume from cardiac output and heart rate, or from left ventricular end-diastolic and end-systolic volumes. Essential for evaluating cardiac performance.

Reviewed by Christopher FloiedPublished Updated

This free online stroke volume calculator provides instant results with no signup required. All calculations run directly in your browser — your data is never sent to a server. Enter your values below and see results update in real time as you type. Perfect for everyday calculations, homework, or professional use.

Results

Stroke Volume

69.4 mL

Stroke Volume Index (est.)

37.5 mL/m²

How to Use This Calculator

1

Enter your input values

Fill in all required input fields for the Stroke Volume Calculator. Most fields include unit selectors so you can work in your preferred unit system — metric or imperial, whichever matches your problem.

2

Review your inputs

Double-check that all values are correct and that you have selected the right units for each field. Incorrect units are the most common source of calculation errors and can produce results that are off by factors of 2, 10, or more.

3

Read the results

The Stroke Volume Calculator instantly computes the output and displays results with units clearly labeled. All calculations happen in your browser — no loading time and no data sent to a server.

4

Explore parameter sensitivity

Try adjusting individual input values to see how the output changes. This is a quick and effective way to develop intuition about how different parameters influence the result and to identify which inputs have the largest effect.

When to Use This Calculator

  • •Use the Stroke Volume Calculator for personal health tracking and wellness monitoring, establishing a baseline and tracking changes over time.
  • •Use it when recording fitness metrics to track progress toward health or athletic goals.
  • •Use it to compare measurements before and after a lifestyle, diet, or training change to quantify the impact.
  • •Use it as a conversation starter before a doctor's appointment, bringing objective data to discuss with a healthcare professional.

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Calculate cardiac output (CO) and cardiac index (CI) from stroke volume and heart rate. Cardiac output is the total volume of blood pumped by the heart per minute.

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About Stroke Volume Calculator

The Stroke Volume Calculator determines the volume of blood ejected from the left ventricle with each heartbeat. Stroke volume is a fundamental hemodynamic parameter that reflects the heart's pumping efficiency. Normal resting SV is 60-100 mL per beat. Combined with heart rate, it defines cardiac output. Stroke volume is influenced by preload (venous return), afterload (vascular resistance), and myocardial contractility. Reduced SV is a hallmark of heart failure, while increased SV characterizes the trained athlete's heart. This calculator derives SV from cardiac output and heart rate.

The Math Behind It

Stroke volume represents the difference between end-diastolic volume (EDV, the blood volume in the ventricle at the end of filling) and end-systolic volume (ESV, the residual volume after contraction): SV = EDV - ESV The ejection fraction (EF = SV/EDV × 100%) is the percentage of blood ejected each beat. Normal EF is 55-70%. An EF below 40% indicates systolic heart failure (HFrEF). **Determinants of stroke volume**: 1. **Preload**: The degree of ventricular stretch at end-diastole, determined by venous return. The Frank-Starling mechanism ensures that greater filling produces greater contractile force, increasing SV up to a physiological limit. 2. **Afterload**: The resistance against which the heart ejects blood. Elevated afterload (hypertension, aortic stenosis) reduces SV because the ventricle must generate more pressure to open the aortic valve. 3. **Contractility**: The intrinsic strength of myocardial contraction, independent of preload and afterload. Enhanced by sympathetic stimulation and inotropic drugs; impaired by ischemia, cardiomyopathy, and negative inotropes. **Normal values**: Resting SV = 60-100 mL. SV index (SV/BSA) = 33-47 mL/m². During exercise, SV increases to 120-140 mL through enhanced venous return and sympathetic contractility, then plateaus at moderate intensity while HR continues to rise. **Clinical applications**: Low SV with high HR suggests heart failure with compensatory tachycardia. High SV with low HR suggests athletic conditioning.

Formula Reference

Stroke Volume

SV = CO × 1000 / HR

Variables: CO in L/min, HR in bpm, SV in mL

SV Index

SVI = SV / BSA

Variables: Normal SVI: 33-47 mL/m²

Worked Examples

Example 1: Normal SV

CO 5.0 L/min, HR 72 bpm

Step 1:SV = 5.0 × 1000 / 72 = 69.4 mL
Step 2:SVI (est.) = 69.4 / 1.85 = 37.5 mL/m²

SV 69 mL, SVI 38 mL/m² — normal resting stroke volume.

Example 2: Heart Failure

CO 3.5 L/min, HR 100 bpm

Step 1:SV = 3.5 × 1000 / 100 = 35 mL
Step 2:SVI = 35 / 1.85 = 18.9 mL/m²

SV 35 mL, SVI 19 mL/m² — severely reduced SV indicating heart failure.

Common Mistakes & Tips

  • !Confusing stroke volume with cardiac output. SV is per beat; CO is per minute (SV × HR).
  • !Using an estimated BSA of 1.85 m² for all patients. Measure or calculate individual BSA for accurate stroke volume index.
  • !Ignoring that SV varies with position (higher supine, lower standing due to venous pooling).

Related Concepts

Cardiac Output Calculator

CO = SV × HR — the product of stroke volume and heart rate.

MAP Calculator

MAP is determined by cardiac output and systemic vascular resistance.

Used in These Calculators

Calculators that build on or apply the concepts from this page:

Cardiac Output Calculator

Heart Failure Life Expectancy Estimator

Frequently Asked Questions

What causes low stroke volume?

Heart failure (reduced contractility), hypovolemia (reduced preload), severe aortic stenosis or hypertension (increased afterload), cardiac tamponade (external compression), and myocardial infarction (loss of contractile tissue) are common causes.

Can stroke volume be too high?

Physiologically elevated SV (100-130+ mL) in athletes is healthy — it's a hallmark of cardiac remodeling from endurance training. Pathologically elevated SV occurs in severe aortic regurgitation, where backflow volume adds to the next beat's volume.

How is SV measured clinically?

Most commonly by echocardiography (measuring left ventricular volumes with Doppler or 2D imaging). Also measurable by cardiac catheterization (thermodilution or Fick method), cardiac MRI, and arterial pulse contour analysis.

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