About the Mean Arterial Pressure Calculator
Mean arterial pressure (MAP) is the average pressure in your arteries across one full heartbeat. Because the heart spends roughly two-thirds of each cycle relaxing (diastole) and one-third contracting (systole), MAP sits closer to the diastolic number than to a simple average of the two readings. This calculator converts a standard blood pressure reading such as 120/80 into MAP and pulse pressure in one step.
Clinicians use MAP as a quick measure of how well blood is reaching vital organs — a MAP of at least about 65 mmHg is a widely used target in hospital and critical care settings. Students, nurses, paramedics and anyone tracking home readings can use it to understand what a reading means beyond the usual systolic/diastolic categories.
The result uses the standard bedside estimate MAP = DBP + ⅓ × (SBP − DBP), which assumes a normal resting heart rate. At very fast heart rates, diastole shortens and the true MAP is slightly higher than this estimate. This tool is educational and does not replace a clinical assessment.
With the default inputs, the mean arterial pressure (map) is 93.3 mmHg. Change any value above to recalculate instantly.
How to use the mean arterial pressure calculator
- 1Take a seated, rested blood pressure reading.
- 2Enter the systolic (top) number.
- 3Enter the diastolic (bottom) number.
- 4Read MAP and pulse pressure, and check the interpretation bands.
Formula and method
The heart spends about one-third of each cardiac cycle in systole and two-thirds in diastole at a normal resting heart rate, so the time-weighted average pressure is (2 × DBP + SBP) ÷ 3 — which is algebraically the same as diastolic pressure plus one-third of the pulse pressure.
Pulse pressure is simply the gap between the systolic and diastolic readings. The one-third rule is an approximation; invasive arterial lines measure MAP directly by integrating the pressure waveform, and at high heart rates the true value is a little higher than this estimate.
- MAP
- Mean arterial pressure (mmHg)
- SBP
- Systolic blood pressure (mmHg)
- DBP
- Diastolic blood pressure (mmHg)
- PP
- Pulse pressure (mmHg)
Worked examples
Textbook reading of 120/80
Pulse pressure is 120 − 80 = 40 mmHg. One-third of that is 13.33, so MAP = 80 + 13.33 = 93.3 mmHg, comfortably inside the usual 65–100 mmHg range.
Stage 2 hypertension reading of 140/90
Pulse pressure is 50 mmHg, so MAP = 90 + 50 ÷ 3 = 106.7 mmHg — above 100, reflecting the raised blood pressure.
Low reading of 90/50
MAP = 50 + 40 ÷ 3 = 63.3 mmHg, just under the 65 mmHg threshold commonly used to judge whether organs are receiving enough blood flow.
Frequently asked questions
What is a normal mean arterial pressure?+
For most adults MAP falls roughly between 65 and 100 mmHg. A reading of 120/80 gives a MAP of about 93 mmHg. Values persistently above 100 usually reflect high blood pressure.
Why is 65 mmHg important?+
A MAP of at least 65 mmHg is a common target in critical care, including sepsis guidelines, because below that level the kidneys, brain and heart may not receive enough blood flow.
Why is MAP not just the average of systolic and diastolic?+
The heart spends about twice as long relaxing as contracting, so the pressure is at diastolic-like levels for most of each beat. MAP therefore weights diastolic pressure twice as heavily as systolic.
What does pulse pressure tell you?+
Pulse pressure (systolic minus diastolic) is normally about 40 mmHg. A persistently wide pulse pressure can reflect stiff arteries, while a very narrow one can occur with low cardiac output. Interpret it with a clinician.
Is the calculated MAP exact?+
No. The one-third formula is an estimate that works best at normal heart rates. Arterial lines in hospital measure MAP directly, and automatic cuffs often compute it from the oscillation signal.
This tool gives general estimates and is not medical advice. Talk to a doctor or qualified professional about your health, diet or training.