Mean arterial pressure calculator (MAP)
Enter your values. The answer and the full worked solution update as you type.
Result
The formula assumes that diastole takes about two thirds of each heartbeat, which holds at normal heart rates; at fast heart rates it underestimates the true MAP. For exam practice only. This is a study aid, never a clinical decision: always follow the prescription, local protocols and the product information.
Calculate the mean arterial pressure (MAP), the average pressure in the arteries over one heartbeat, from a systolic and diastolic blood pressure. The calculator also gives the pulse pressure and shows both forms of the formula, so you can check a hand calculation for nursing or physiology exams.
Step-by-step solution
Pulse pressure = systolic − diastolic
Mean arterial pressure
Key formulas
- Mean arterial pressure
- MAP = (SBP + 2·DBP)/3 = DBP + PP/3
How to calculate mean arterial pressure
- Find the pulse pressure: systolic minus diastolic, for example 120 − 80 = 40 mmHg.
- Add one third of the pulse pressure to the diastolic pressure: MAP = 80 + 40/3 = 93.3 mmHg.
- Or use the equivalent form MAP = (SBP + 2 × DBP)/3 = (120 + 160)/3 = 93.3 mmHg.
- Compare with the threshold in the question; a MAP of at least 65 mmHg is a commonly quoted minimum for organ perfusion.
Questions and answers
Why does the diastolic pressure count twice?
At a normal heart rate the heart spends about two thirds of each beat in diastole, so the average pressure is closer to the diastolic value.
What is a normal MAP?
Roughly 70 to 100 mmHg in healthy adults. Exam questions often state that a MAP of at least 60 to 65 mmHg is needed to perfuse the brain, heart and kidneys.
Is the formula always accurate?
It is an estimate. At fast heart rates diastole gets shorter and the formula underestimates the true MAP; an arterial line measures the MAP directly.
What is the pulse pressure?
The difference between systolic and diastolic pressure, normally about 40 mmHg. Stiff arteries widen it; it narrows, for example, in shock or cardiac tamponade.