Critical care
Mean arterial pressure calculator
Calculate mean arterial pressure (MAP) with the standard formula from a systolic and diastolic blood pressure — see the full worked setup and the pulse pressure behind the answer, not just the number. Free, no signup, runs in your browser.
Interactive calculator
Mean arterial pressure (MAP) calculator
Enter a systolic and diastolic blood pressure in mmHg to calculate the mean arterial pressure with the standard formula, and see the worked setup below. Results update as you type.
Result
Enter a systolic and diastolic pressure to see the MAP and the worked setup.
For education and practice only. The ~65 mmHg perfusion figure is a commonly cited teaching reference, not a directive from this site — real hemodynamic decisions require independent verification.
How it works
The MAP formula
Mean arterial pressure weights the diastolic pressure twice because, at a normal resting heart rate, the heart spends roughly two-thirds of each cardiac cycle in diastole. Two equivalent forms give the same answer.
Mean arterial pressure (mmHg)
MAP = (SBP + 2 × DBP) ÷ 3
Add the systolic pressure to twice the diastolic pressure, then divide by three. SBP is the systolic (top) number and DBP the diastolic (bottom) number, both in mmHg.
Equivalent form (pulse pressure)
MAP = DBP + (pulse pressure ÷ 3)
Pulse pressure is SBP − DBP. Adding one-third of it to the diastolic pressure gives the same MAP as the first formula — a handy mental check at the bedside.
Worked example
A MAP calculation, step by step
The reading
A blood pressure of 120/80 mmHg — systolic 120, diastolic 80. What is the mean arterial pressure?
The setup
- 1. Pulse pressure: 120 − 80 = 40 mmHg.
- 2. MAP = (120 + 2 × 80) ÷ 3 = (120 + 160) ÷ 3.
- 3. = 280 ÷ 3 = 93.3 mmHg.
Answer: 93.3 mmHg.
Reading the result
A MAP of 93.3 mmHg sits within the general normal range of about 70–100 mmHg and is well above the commonly cited ~65 mmHg perfusion threshold.
By contrast, a reading of 90/50 gives (90 + 100) ÷ 3 = 63.3 mmHg, which falls below that commonly cited ~65 mmHg figure — the kind of value that, in study scenarios, prompts closer monitoring.
Enter 120 and 80 in the calculator above to see this exact worked setup returned, then try 90 and 50 to watch the threshold note change.
Common questions
Mean arterial pressure, explained
The standard formula is MAP = (SBP + 2 × DBP) ÷ 3, where SBP is the systolic and DBP the diastolic pressure in mmHg. An equivalent form is MAP = DBP + (pulse pressure ÷ 3), where pulse pressure = SBP − DBP. Diastole is weighted twice because the heart spends roughly two-thirds of the cardiac cycle in diastole at a normal resting heart rate.
MAP represents the average pressure driving blood through the systemic circulation across the whole cardiac cycle, so it is generally considered a better indicator of perfusion to organs such as the brain, heart, and kidneys than a single systolic reading. A systolic value can look reassuring while the average driving pressure is low, which is why MAP is watched closely in critical care.
A normal MAP is generally described as roughly 70–100 mmHg in adults. Values vary with age, activity, and clinical context, so this is a general educational range rather than a fixed cutoff — this tool is for study and practice, not for guiding real treatment.
A MAP of about 65 mmHg or higher is commonly cited as the minimum generally needed to adequately perfuse vital organs. It is a widely referenced teaching figure, not a rule that this site sets, and actual targets are individualized by clinicians for each patient. We include it only as general educational context.
Pulse pressure is the difference between systolic and diastolic pressure (SBP − DBP). For a 120/80 reading, pulse pressure is 40 mmHg. It appears in the alternate MAP formula, MAP = DBP + (pulse pressure ÷ 3), and is itself a useful teaching value — a narrow or wide pulse pressure can be a clinical talking point in your studies.
Yes. It is completely free, needs no account, and runs entirely in your browser, so it works on a phone. It is a study and practice aid only — it does not provide medical advice, and any real hemodynamic assessment requires clinical judgment and an independent double-check.
Keep the momentum
From the number to the bedside picture
MAP is one piece of the hemodynamic picture. Practice the wider med-surg question bank, run a dosage calculation for the drips that support it, or explore the other free calculators.
This calculator and all study material on this site are provided for practice and study only. Verify every value and decision against the order and institutional policy.
More free tools
Related calculators
Reach for these alongside this one — the calculations that most often come up together on the wards and in practice questions.
Glasgow Coma Scale (GCS) Calculator
Score eye, verbal, and motor response to grade level of consciousness.
Anion Gap Calculator
Serum anion gap to work up metabolic acidosis (MUDPILES vs. non-gap).
Parkland Formula Calculator
24-hour burn fluid resuscitation volume and hourly rates from %TBSA and weight.
Practice these — free questions
Apply it on real NCLEX-style questions
A calculator hands you the number; the exam makes you reach it under pressure and defend it. Drill Medical-Surgical questions that put this calculation inside a realistic clinical scenario — each one with a written rationale, so you learn why the answer is right, not just what it is. That explained-rationale practice is what sets us apart from a bare calculator.
Free · no spam
Get a free high-yield NCLEX question every week
One carefully written practice question plus a short study tip, emailed weekly. Unsubscribe anytime — we never share your address.