Stroke Volume Calculator

Human Physiology • Cardiovascular Physiology

Written by STEM Calculators Team Published April 13, 2026 Updated April 13, 2026

Stroke volume calculator

Compute stroke volume from end-diastolic volume and end-systolic volume, optionally add ejection fraction, compare two physiological states, and inspect how EDV and ESV shape cardiac ejection.

Calculator mode

Beginner mode focuses on direct volume inputs. Advanced mode adds preload, afterload, and contractility interpretation aids.

Quick comparison preset

Compare two physiological states

Include ejection fraction output

State A

Label

Preset

Volume unit

End-diastolic volume (EDV)

End-systolic volume (ESV)

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Optional columns: label,edv,esv,unit,preload,afterload,contractility. Use one or two rows for one state or comparison mode.

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Stroke volume and ventricular ejection

A stroke volume calculator estimates how much blood one ventricle ejects with each heartbeat. The main computed quantity is stroke volume, and the same inputs can also be used to summarize end-diastolic volume, end-systolic volume, and optional ejection fraction in a clear physiological context.

Stroke volume depends directly on the difference between ventricular filling before contraction and the blood left behind after contraction. This makes the stroke volume calculator useful for understanding how preload, afterload, and contractility affect cardiac performance in resting and altered physiological states.

Core definitions and formulas

End-diastolic volume, or EDV, is the ventricular volume at the end of filling. End-systolic volume, or ESV, is the volume remaining after contraction. Stroke volume is the amount ejected in one beat, and ejection fraction expresses that ejected amount relative to EDV.

\[ \begin{aligned} SV &= EDV - ESV \end{aligned} \] \[ \begin{aligned} EF &= \frac{SV}{EDV} \cdot 100 \end{aligned} \]

In these expressions, EDV, ESV, and SV are usually reported in mL, while EF is reported as a percentage. A larger EDV generally supports a larger stroke volume if the ventricle can eject effectively, whereas a larger ESV means more blood remains after systole and therefore reduces stroke volume.

How to interpret results

A higher stroke volume usually means the ventricle is ejecting more blood per beat, which may occur with increased preload or increased contractility. A lower stroke volume may reflect reduced filling, reduced contractility, or increased afterload that makes ejection harder. Ejection fraction helps distinguish how effectively the ventricle empties relative to its filled volume.

When comparison mode is used, the most important question is whether the second state changes EDV, ESV, or both. For example, exercise often raises EDV slightly and lowers ESV, so stroke volume usually increases. Reduced contractility or high afterload often raises ESV, which lowers stroke volume.

Common pitfalls

Entering ESV larger than EDV, which gives a non-physiological result.
Mixing mL and L without converting units correctly.
Assuming ejection fraction and stroke volume always change in the same direction.
Ignoring the effect of preload, afterload, and contractility on interpretation.

Micro example: if EDV = 120 mL and ESV = 50 mL, then \(SV = 120 - 50 = 70\) mL. The ejection fraction is \(EF = 70/120 \cdot 100 \approx 58.3\%\).

This tool is best used for basic cardiovascular physiology, ventricular performance comparisons, and introductory hemodynamic reasoning. It does not replace full clinical assessment; the next step for broader analysis is often cardiac output, pressure-volume relationships, or arterial pressure and resistance calculations.

Frequently Asked Questions

What does a stroke volume calculator measure?

It calculates how much blood one ventricle ejects in a single heartbeat. The result is found from the difference between end-diastolic volume and end-systolic volume.

How is stroke volume calculated from EDV and ESV?

Stroke volume is calculated with the formula SV = EDV - ESV. If EDV is 120 mL and ESV is 50 mL, the stroke volume is 70 mL.

What is the difference between stroke volume and ejection fraction?

Stroke volume is the actual amount of blood ejected per beat, usually in mL. Ejection fraction is the percentage of EDV that is ejected, calculated as SV divided by EDV times 100.

Why can stroke volume decrease even if EDV stays the same?

Stroke volume decreases when more blood remains in the ventricle after systole, which means ESV rises. This can happen with reduced contractility or increased afterload.

When is comparison mode useful in a stroke volume calculator?

Comparison mode is useful for checking how two conditions differ, such as rest versus exercise or normal contractility versus reduced contractility. It helps show whether the ventricle ejects more or less blood in the second state.

Stroke Volume Calculator

State A

State B

Paste or import CSV data

Calculation steps

Ventricular volume bars

Highlighted stroke volume bar

Pressure-volume style schematic

Side-by-side state comparison

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Frequently Asked Questions

State A

State B

Paste or import CSV data

Calculation steps

Ventricular volume bars

Highlighted stroke volume bar

Pressure-volume style schematic

Side-by-side state comparison

Rate this calculator

Frequently Asked Questions

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