Ejection Fraction Calculator
Calculate cardiac ejection fraction from end-diastolic and end-systolic volumes.
Shows stroke volume, cardiac output, and clinical classification.
Ejection fraction (EF) is the percentage of blood pumped out of the left ventricle with each heartbeat. A normal heart does not eject all the blood it contains — it fills to an end-diastolic volume (EDV) and contracts down to an end-systolic volume (ESV), ejecting the difference.
EF = (EDV - ESV) / EDV × 100%
Stroke volume (SV) = EDV - ESV. This is the actual volume of blood ejected per beat.
Cardiac output (CO) = SV × heart rate. At rest with a heart rate of 70 bpm and stroke volume of 70 mL: CO = 4,900 mL/min ≈ 4.9 liters/minute, which is typical.
Clinical classification of left ventricular EF:
- Normal: EF ≥ 55% (most guidelines use 52-55% as the lower bound)
- Mildly reduced: 41-54%
- Moderately reduced: 30-40%
- Severely reduced: < 30%
Heart failure with reduced ejection fraction (HFrEF) is defined as EF below 40%. This type was historically called systolic heart failure. It responds well to evidence-based medications including ACE inhibitors, beta-blockers, and SGLT2 inhibitors.
Heart failure with preserved ejection fraction (HFpEF) — EF ≥ 50% — is increasingly recognized as its own entity where the problem is stiffness of the ventricle wall during filling rather than pump failure. It carries a similar prognosis but responds less well to current medications.
EF is measured by echocardiography, cardiac MRI, or nuclear imaging. Echocardiography is most common given its availability and lack of radiation exposure.
This calculator is for educational purposes. Clinical decisions require physician evaluation and imaging confirmation.
How we build and check this calculator
This calculator runs entirely in your browser, so the numbers you enter stay on your device. The math behind it is written by hand and tested against worked examples and standard references before the page goes live.
SuperGlobalCalculator is independently built and maintained. See how we build and verify our calculators.