Mean Arterial Pressure (MAP) Calculator
Work out mean arterial pressure from a blood-pressure reading — or average a list of home readings — with pulse pressure, the blood-pressure category, heart-rate-corrected and alternative MAP formulas, kPa units and cerebral perfusion pressure.
How it works
MAP = diastolic + (systolic − diastolic) ÷ 3 · pulse pressure = systolic − diastolic · Meaney: MAP = DBP + 0.412 × PP · heart-rate corrected (Razminia): MAP = DBP + (0.33 + 0.0012 × HR) × PP · CPP = MAP − ICP · 1 kPa = 7.5006 mmHg
Mean arterial pressure is the average pressure in your arteries over a single cardiac cycle, and it matters more than either number alone for whether blood actually reaches your organs. Because the heart spends about twice as long in diastole (relaxing) as in systole (contracting), the standard formula weights the diastolic number two-thirds and adds one-third of the pulse pressure. A MAP around 70–100 mmHg is typical; sustained values much below 60–65 mmHg can mean organs are not being perfused well. The calculator also gives the pulse pressure and the blood-pressure category, converts to kPa, and lets you switch formulas: Meaney’s 0.412 factor fits automated readings slightly better, and the Razminia correction adds weight to the systolic number as heart rate rises, because diastole shortens. In “Several readings” mode, paste readings from a home monitor to get the average MAP, the average reading and a chart. Clinicians can add intracranial pressure to get cerebral perfusion pressure.
Worked example
For a 120/80 reading: pulse pressure = 40 mmHg and MAP = 80 + 40 ÷ 3 = 80 + 13.3 = 93.3 mmHg — inside the typical 70–100 mmHg range. Under the 2017 ACC/AHA cut-offs a diastolic of exactly 80 already counts as stage 1 hypertension, so the category shows stage 1. With a pulse of 100 bpm the heart-rate-corrected MAP is 80 + (0.33 + 0.12) × 40 = 98.0 mmHg. Four home readings of 128/84, 122/80, 135/86 and 118/78 average 126/82 mmHg with a mean MAP of 96.6 mmHg.
Sources: American Heart Association — Understanding Blood Pressure Readings · Meaney E et al. (2000) — Formula and nomogram for the sphygmomanometric calculation of the mean arterial pressure, Heart · Razminia M et al. (2004) — Validation of a new formula for mean arterial pressure calculation · Surviving Sepsis Campaign — International guidelines (MAP target 65 mmHg)
Frequently asked questions
Why is diastolic weighted more than systolic?
At a normal resting heart rate the heart spends about two-thirds of each cycle relaxed (diastole) and one-third contracting (systole), so the diastolic pressure influences the average more. The standard formula reflects that 2:1 split.
What MAP is too low?
A MAP below roughly 60–65 mmHg may not push enough blood through the organs, which is why critical-care guidance often targets at least 65 mmHg. Any low reading with symptoms needs medical assessment, not a calculator.
Is this formula exact?
It is a well-established estimate that assumes a normal heart rate. At fast heart rates diastole shortens and the true MAP sits closer to the systolic number, so the standard formula slightly underestimates it; enter your pulse to see the heart-rate-corrected value. Arterial lines measure MAP directly.
What is pulse pressure?
The difference between systolic and diastolic pressure — 40 mmHg for 120/80. A pulse pressure above about 60 mmHg is considered wide and is common with stiffening arteries in older adults.
Can I average several readings?
Yes. Choose “Several readings”, paste one reading per line (for example 128/84 72) and the calculator gives the average MAP, the average blood pressure and its category, which is how guidelines judge blood pressure.
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Educational estimate, not medical advice — for clinical decisions consult a healthcare professional.