Mean Arterial Pressure (MAP) Calculator
Estimate the mean arterial pressure — the average pressure in your arteries over one heartbeat — from a standard blood-pressure reading. MAP reflects the perfusion pressure reaching your organs better than the systolic number alone. Enter your systolic and diastolic values in mmHg.
The MAP formula
MAP = DBP + (SBP − DBP) ÷ 3 = (SBP + 2 × DBP) ÷ 3, where SBP is systolic and DBP is diastolic pressure in mmHg. The pulse pressure (SBP − DBP) is weighted by one third because diastole occupies about two thirds of the cardiac cycle at a normal heart rate.
Frequently asked questions
What is the mean arterial pressure formula?
MAP is estimated as the diastolic pressure plus one third of the pulse pressure: MAP = DBP + (SBP − DBP) ÷ 3, which is the same as (SBP + 2 × DBP) ÷ 3. For example, a blood pressure of 120/80 mmHg gives MAP = 80 + (120 − 80) ÷ 3 ≈ 93 mmHg. The diastolic value is weighted more heavily because the heart spends about two thirds of each cycle in diastole.
What is a normal mean arterial pressure?
A MAP of roughly 70–100 mmHg is generally considered normal for a resting adult. A MAP of at least 60–65 mmHg is usually needed to perfuse the vital organs; sustained values below that can signal inadequate blood flow, while persistently high values reflect hypertension. Your clinician interprets MAP alongside your overall picture.
Why use MAP instead of the top blood-pressure number?
Systolic pressure is only the brief peak of each heartbeat. MAP represents the average driving pressure across the whole cycle, so it correlates more closely with the actual perfusion of organs such as the brain, kidneys and heart. It is widely used in critical care and anaesthesia, where maintaining an adequate MAP is a common treatment target.
Is this MAP estimate exact?
This mean arterial pressure figure is an estimate, not a measurement. The one-third pulse-pressure formula is an approximation that works well at normal heart rates but drifts at very high rates, in irregular rhythms, or when arterial stiffness changes the pressure waveform. An arterial line measures MAP directly and is used when a precise value matters. Treat this calculator as an educational estimate, not a diagnosis.
What is pulse pressure?
Pulse pressure is simply the difference between the systolic and diastolic readings — 40 mmHg for a 120/80 reading. It is the quantity divided by three and added to the diastolic value in the MAP formula. A wide or narrow pulse pressure can itself be clinically meaningful, so it is shown alongside your MAP result.
This is a reference tool, not a diagnosis or medical advice. Results depend on the laboratory, assay and clinical context, and reference intervals vary between labs and by age and sex — always read your result against the range printed on your own report and discuss it with a qualified healthcare professional.
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