By Zencalcy Editorial TeamLast reviewed About us
Ejection fraction is the share of the left ventricular volume that is ejected with each beat. It is calculated from end-diastolic and end-systolic volumes and is used to describe systolic function. This calculator returns the percentage and places it in the usual normal, mildly reduced or reduced ranges.
The percentage of ventricular volume ejected per beat.
EF = (EDV − ESV) ÷ EDV × 100
An ejection fraction of 50% or more is commonly described as normal, 40–49% as mildly reduced and below 40% as reduced. These bands describe systolic function in the context of heart failure; they are not a diagnosis on their own, and a normal value does not exclude diastolic dysfunction or other cardiac disease.
| Symbol | Meaning |
|---|---|
| EDV | End-diastolic volume in millilitres. |
| ESV | End-systolic volume in millilitres. |
| EF | Ejection fraction as a percentage of end-diastolic volume. |
Stroke volume = 120 − 50 = 70 mL, so EF = 70 ÷ 120 × 100 = 58.3%, which is normal. With EDV 100 mL and ESV 60 mL, stroke volume is 40 mL and EF is 40.0%, in the mildly reduced range. EDV 100 mL with ESV 70 mL gives 30.0%, which is reduced.
Ejection fraction describes emptying, not filling. A ventricle can eject a normal percentage of a normal volume and still be abnormal because its walls are thick and stiff. Conversely, a dilated ventricle can have a low percentage simply because it holds a large residual volume. That is why reporting standards pair EF with chamber dimensions and why the same percentage can mean different things in different hearts. The measurement also depends on loading conditions and on how the endocardial border is traced. Automated software and visual estimates can differ, particularly in poor image windows. Use the number as one part of an imaging report and a clinical assessment. It matters for treatment decisions in reduced systolic function, but it should not be used to reassure or alarm someone without the rest of the picture.
Continue with the Mean Arterial Pressure Calculator, Pulse Pressure Calculator, or the QTc Calculator — or browse more cardiology tools and all health calculators.
Around 50% or higher is commonly described as normal for the left ventricle. Values between 40% and 49% are mildly reduced, and below 40% is reduced. The exact reference range depends on the imaging method and laboratory.
Blood pressure, ECG and risk scores are screening aids, not diagnoses. A single reading can be misleading; trends and proper technique matter. Scores estimate population risk and do not replace clinical assessment, anticoagulation decisions or emergency care.
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Last reviewed: September 2026. See how we build and check every tool on the about page.
Content updated: September 2026