Pulse Pressure Calculator.

Every blood pressure reading has two numbers. The top (systolic) is the pressure when your heart contracts; the bottom (diastolic) is the resting pressure between beats. Pulse pressure is simply the difference between them. For a textbook 120/80 reading, the pulse pressure is 40 mmHg.

That gap tells you something the two numbers alone do not: how much your arteries stretch and recoil with each heartbeat. A healthy, elastic aorta cushions the surge of blood so the pressure difference stays moderate. As arteries stiffen with age, the aorta cushions less, systolic pressure climbs, and the gap widens.

A wide pulse pressure (above ~60 mmHg) is, in adults over 50, one of the better single-number predictors of cardiovascular risk — it reflects large-artery stiffness and is associated with higher rates of heart attack, stroke, and atrial fibrillation. It usually rises because systolic pressure increases while diastolic stays flat or even falls.

A narrow pulse pressure (below ~40 mmHg) points the other way: the heart may be ejecting less blood per beat. Causes range from the benign (a naturally low reading) to the significant — heart failure, aortic valve stenosis, or major blood loss. On its own a narrow reading is rarely an emergency, but a persistent one is worth raising with a clinician.

This tool also reports mean arterial pressure (MAP) — the average pressure across a full cardiac cycle, estimated as diastolic + pulse pressure ÷ 3. MAP above ~60 mmHg is generally needed to perfuse the organs; clinicians watch it closely in critical care.

Blood pressure swings through the day with stress, caffeine, posture, and time since your last meal. A single reading is a snapshot, not a verdict. Use an average of several seated, rested measurements, and treat a widened or narrowed pulse pressure as a prompt to talk to your clinician — not a diagnosis.