Stroke volume is the amount of blood the heart pumps with each beat. Combined with heart rate, it determines cardiac output. Stroke volume can be calculated from EDV − ESV (the difference between end-diastolic and end-systolic ventricular volumes), or from cardiac output divided by heart rate. Our stroke volume calculator handles both methods and computes ejection fraction (SV / EDV × 100), categorizing it per the ACC/AHA heart failure framework: ≥55% normal, 41-54% mildly reduced (HFmrEF), ≤40% reduced (HFrEF).
Input end-diastolic and end-systolic volumes from echo or MRI.
Alternatively enter cardiac output and heart rate.
Review stroke volume, ejection fraction, and EF category.
Stroke volume measures how much blood leaves the ventricle on each contraction. Ejection fraction expresses it as a percentage of the ventricle's filled volume — it's the gold-standard metric for assessing heart pumping function. Normal EF is 55-70%; below 40% indicates heart failure with reduced ejection fraction (HFrEF).
SV = EDV − ESV • EF = SV / EDV × 100 • SV = CO × 1000 / HR
Normal stroke volume: 60-100 mL per beat for adults
Normal ejection fraction: 55-70%
EF 41-54% = mildly reduced (HFmrEF) per ACC/AHA
EF ≤40% = reduced (HFrEF) — heart failure with reduced ejection fraction
Athletes have larger SV (90-120 mL) due to chamber enlargement and stronger contractility
Both EDV and ESV are measured by echocardiography, MRI, or radionuclide ventriculography
Stroke volume — the amount of blood the left ventricle ejects with each heartbeat — is a critical indicator of cardiac function. In a healthy adult at rest, stroke volume averages 60-100 milliliters per beat, and when multiplied by heart rate, yields cardiac output (typically 4.5-5.5 liters per minute at rest). The primary formula for stroke volume is end-diastolic volume (EDV) minus end-systolic volume (ESV), representing the difference between the blood filling the ventricle and what remains after contraction. Ejection fraction, calculated as stroke volume divided by EDV, is one of the most important metrics in cardiology — a normal ejection fraction of 55-70% indicates healthy pump function, while values below 40% suggest heart failure with reduced ejection fraction (HFrEF). Three key physiological mechanisms regulate stroke volume: preload (the stretch of ventricular walls before contraction, governed by the Frank-Starling mechanism), afterload (the resistance the heart must pump against), and contractility (the intrinsic strength of cardiac muscle). During exercise, stroke volume can increase by 50-60% through enhanced venous return and sympathetic stimulation, which is why athletes often have resting stroke volumes exceeding 100 mL.
Ejection fraction is the single most important number in heart failure care. It guides treatment selection (different drugs work for HFrEF vs HFpEF), prognosis (lower EF correlates with worse outcomes), and response to therapy. An EF measurement is part of every cardiology workup for suspected heart failure or after a heart attack.
Data sourced from trusted institutions
All formulas verified against official standards.