Mean Arterial Pressure (MAP) Calculator
Calculate mean arterial pressure from systolic and diastolic readings — the perfusion pressure that determines blood flow to organs, and a key target in critical care.
❤️ Clinical Reference📐 MAP = DBP + (SBP − DBP) / 3🏥 Health
Systolic BP (mmHg)
Diastolic BP (mmHg)
Heart rate (bpm, for tachycardia adjustment)
Please enter valid values.
Formula & Reference
| Variable | Symbol | Formula | Units |
|---|---|---|---|
| Mean Arterial Pressure (MAP) Calculator | — | MAP = DBP + (SBP − DBP) / 3 | mmHg |
Step-by-Step Examples
Example 1
Normal Blood Pressure
120/80 mmHg.
- Pulse pressure = 120 − 80 = 40
- MAP = 80 + 40/3
- MAP = 93.3 mmHg
✓ MAP 93 mmHg — normal
Example 2
Hypotensive
85/50 mmHg.
- Pulse pressure = 35
- MAP = 50 + 35/3
- MAP = 61.7 mmHg
- Below the commonly cited 65 mmHg target
✓ MAP 62 mmHg — below target
Example 3
Wide Pulse Pressure
160/60 mmHg.
- Pulse pressure = 100 — unusually wide
- MAP = 60 + 100/3
- MAP = 93.3 mmHg
- Identical MAP to 120/80 despite very different physiology
✓ MAP 93 mmHg — same MAP, different picture
Real-World Applications
Critical Care Targets
A MAP of at least 65 mmHg is a widely used resuscitation target in sepsis and shock management.
Cerebral Perfusion
Cerebral perfusion pressure is calculated as MAP minus intracranial pressure, making MAP central to neurocritical care.
Vasopressor Titration
Vasoactive infusions in intensive care are typically titrated to a MAP target rather than to systolic pressure.
Renal Perfusion
Sustained low MAP is associated with acute kidney injury, since renal blood flow depends on adequate perfusion pressure.
Common Mistakes to Avoid
⚠️
Assuming MAP is the simple average of systolic and diastolic
It is not. Diastole occupies roughly two-thirds of the cardiac cycle at normal heart rates, which is why the formula weights diastolic pressure twice as heavily.
⚠️
Using the standard formula during marked tachycardia
At high heart rates diastole shortens relative to systole, so the standard one-third weighting underestimates MAP. Adjusted formulas exist for this.
⚠️
Treating 65 mmHg as universal
The 65 mmHg target comes from sepsis trials. Patients with chronic hypertension may require higher pressures to maintain organ perfusion.
Frequently Asked Questions
How is mean arterial pressure calculated? ▾
Diastolic pressure plus one third of the pulse pressure — that is, DBP + (SBP − DBP) / 3.
What is a normal MAP? ▾
Roughly 70 to 100 mmHg in healthy adults, with 65 mmHg commonly used as a lower target in critical care resuscitation.
Why isn't MAP the average of systolic and diastolic? ▾
Because the heart spends about two thirds of each cycle in diastole at normal rates, so diastolic pressure contributes proportionally more to the time-weighted average.
Why is MAP more useful than systolic pressure in shock? ▾
MAP represents the driving pressure for organ perfusion across the whole cardiac cycle, which is what determines blood flow to tissues.
Does the formula change at high heart rates? ▾
Yes — as diastole shortens, the standard one-third weighting underestimates MAP, and adjusted formulas weighting pulse pressure more heavily are sometimes used.