Ejection Fraction Calculator

Written by Great Medico

Updated September 24, 2026 •2 min read

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Cardiovascular numbers become useful only when the equation behind them is clear. Ejection Fraction Calculator turns the specific measurements in this tool into a focused hemodynamic or risk estimate.

What this calculator does

Ejection Fraction Calculator uses I know…, End-diastolic volume (EDV), Stroke volume, End-systolic volume (ESV), Cardiac output, and Heart rate to calculate left-ventricular ejection fraction. It is built around the exact fields displayed in this plugin rather than a generic version of the topic. Where supported, it also shows Stroke volume and End-systolic volume so the primary result is easier to place in context. Cardiovascular formulas are sensitive to measurement technique and clinical context. A mathematically correct output can still be misleading if the input was obtained under a different physiologic condition, with a different assay, or outside the population for which the score was developed.

How to use it

Enter or select I know…, End-diastolic volume (EDV), Stroke volume, End-systolic volume (ESV), Cardiac output, and Heart rate. Use the units offered by the calculator and choose the option that matches the actual clinical or timing situation. Check date entries and laboratory units before relying on the output. When the formula combines measurements, use values obtained under the same assessment or physiologic conditions whenever possible.

How the calculation works

Ejection fraction is stroke volume divided by end-diastolic volume × 100. Depending on the selected input mode, stroke volume is entered directly, calculated as EDV − ESV, or derived from cardiac output and heart rate as CO × 1000 / HR. The engine checks that stroke volume falls between zero and EDV, then also reports the corresponding end-systolic volume.

Example

Using the sample values prefilled in this calculator, the primary result is 58.33 % (Ejection fraction), Stroke volume is 70 mL, and End-systolic volume is 50 mL. This worked example shows how the plugin’s own default inputs flow through the implemented method; replace them with the correct patient, laboratory, imaging, or personal values before interpreting a result.

How to interpret the result

Read the output as ejection fraction generated by this specific formula or score. The number is most useful when compared with the clinical context and, when appropriate, serial measurements or the current guideline pathway for the condition. A boundary value should not be overinterpreted as a sudden change in physiology.

Limitations and notes

Cardiovascular formulas are sensitive to measurement technique and clinical context. A mathematically correct output can still be misleading if the input was obtained under a different physiologic condition, with a different assay, or outside the population for which the score was developed.