What Is Mean Arterial Pressure?
Mean arterial pressure, shortened to MAP, is the average pressure pushing blood through the arteries during one cardiac cycle. It sits closer to the diastolic pressure than the systolic pressure because the heart usually spends more time resting between beats than contracting.
MAP helps describe the pressure available to move blood toward organs. It does not prove that every tissue is receiving enough oxygen. Blood flow also depends on cardiac output, blood-vessel resistance, oxygen level and the person’s condition.
How to Calculate Mean Arterial Pressure
The common adult formula uses systolic blood pressure, or SBP, and diastolic blood pressure, or DBP. Both values must come from the same reading and use millimeters of mercury, written as mmHg.
The same calculation can be written with pulse pressure. Pulse pressure is systolic pressure minus diastolic pressure.
- 1
Double the diastolic pressure: 2 × 80 = 160
- 2
Add the systolic pressure: 160 + 120 = 280
- 3
Divide by three: 280 ÷ 3 = 93.3 mmHg
This formula estimates the time-weighted pressure for a usual adult cardiac cycle. A bedside monitor may show a measured or device-derived MAP instead. Do not recalculate that displayed MAP unless the clinical workflow calls for it.
How to Use This MAP Calculator
- 1
Use one blood pressure reading
Take the systolic and diastolic numbers from the same cuff measurement.
- 2
Enter the top number
Systolic pressure is measured while the heart contracts.
- 3
Enter the bottom number
Diastolic pressure is measured while the heart relaxes between beats.
- 4
Review the full result
Read the MAP, pulse pressure, working equation and blood pressure pattern together.
For a home reading, sit quietly first, support your arm and follow the instructions supplied with a validated cuff. One unusual reading may be caused by movement, poor cuff fit, stress, pain, caffeine or recent exercise.
Mean Arterial Pressure Range and Result Context
MAP does not have one universal “normal” cutoff for every person. Many educational references place usual adult values around 70 to 100 mmHg. In critical care, a different question is often being asked: is pressure high enough to support organ perfusion during serious illness?
Sustained values in this area may be linked with reduced organ perfusion, especially during acute illness.
This is close to, but below, the initial 65 mmHg target used for many adults with septic shock.
This broad band is context only. It does not confirm that blood pressure or circulation is healthy.
Interpret the original systolic and diastolic values using current blood pressure guidance.
MAP vs Blood Pressure vs Pulse Pressure
Systolic pressure
The upper blood pressure number. It reflects pressure while the heart contracts.
SBPDiastolic pressure
The lower number. It reflects pressure between heartbeats.
DBPPulse pressure
The gap between systolic and diastolic pressure.
PP = SBP − DBPMean arterial pressure
An estimate of average arterial pressure across one cardiac cycle.
MAP ≈ DBP + ⅓PPThe American Heart Association classifies adult blood pressure from the systolic and diastolic numbers, not MAP alone. That is why the calculator shows the blood pressure pattern separately from the MAP estimate.
What Determines Mean Arterial Pressure?
MAP is shaped by how much blood the heart pumps and how much resistance the blood meets in the circulation. A simplified physiology relationship is:
This relationship explains why a MAP result cannot identify the cause of a high or low value. Cardiac output may change with heart rate and stroke volume. Vascular resistance may change with blood-vessel tone, medicine, temperature and illness.
If you need to estimate blood flow per minute, use the Cardiac Output Calculator. That calculation answers a different question and should not be treated as a replacement for MAP.
Calculated MAP vs Arterial-Line MAP
Blood pressure cuff
The calculator uses SBP and DBP from a cuff, then applies the one-third pulse-pressure formula. The answer depends on the cuff reading and the assumptions inside the equation.
Arterial line
An arterial catheter captures the pressure waveform over time. A monitor derives MAP from the area under that waveform, so the displayed result is not merely the cuff formula.
During unstable illness, surgery or vasopressor treatment, clinicians use the monitor, symptoms, laboratory findings and the whole hemodynamic picture. An online estimate should never overrule bedside data.
Important Limits and Common Errors
- Fast or irregular heart rhythm: the one-third estimate assumes a usual split between systole and diastole. That split changes as heart rate rises.
- Wrong cuff size or position: an inaccurate blood pressure reading produces an inaccurate MAP estimate.
- Mixing two readings: do not combine systolic pressure from one reading with diastolic pressure from another.
- Pediatric use: children and newborns need age-specific blood pressure and perfusion assessment.
- Pregnancy: symptoms and pregnancy-specific blood pressure guidance matter. Do not use MAP alone to judge risk.
- Critical illness: a treatment target depends on diagnosis, age, usual pressure, medicines and the care plan.
- Pulmonary pressure: mean pulmonary artery pressure is a separate measurement. This page calculates systemic MAP only.
When a Blood Pressure Reading Needs Prompt Help
Do not wait for a MAP calculation when symptoms suggest an emergency. The American Heart Association advises calling 911 in the United States when blood pressure is higher than 180/120 mmHg and there are symptoms such as chest pain, shortness of breath, back pain, numbness, weakness, vision change or difficulty speaking.
For chest-pain triage education, see the HEART Score for Chest Pain. It is a separate emergency-department score and is not intended for self-diagnosis at home.
Mean Arterial Pressure FAQs
How do you calculate mean arterial pressure?
For a standard adult cuff reading, use MAP ≈ (SBP + 2 × DBP) ÷ 3. An equivalent formula is MAP ≈ DBP + one-third of the pulse pressure.
What is the MAP for a blood pressure of 120/80?
The estimated MAP is 93.3 mmHg. The calculation is (120 + 2 × 80) ÷ 3. Pulse pressure is 120 − 80, which equals 40 mmHg.
Why is diastolic pressure doubled?
At a usual resting heart rate, diastole takes more of the cardiac cycle than systole. The standard formula gives the diastolic value more weight to reflect that timing.
Is a MAP of 65 normal?
It is not a universal normal value. A MAP of 65 mmHg is used as an initial treatment target for many adults with septic shock. Home and outpatient readings must be judged from the full blood pressure, symptoms and personal context.
Is calculated MAP the same as arterial-line MAP?
No. This page estimates MAP from cuff values. An arterial line records the pressure waveform continuously, and the monitor derives its MAP from that waveform.
Evidence and Editorial Notes
The formula, limitations and safety notes on this page were checked against physiology references and current guidance.
- NCBI Bookshelf: Cardiovascular Physiology — MAP and pulse-pressure relationships.
- Cardiovascular Monitoring: Physiological and Technical Considerations — time-weighted pressure and the standard estimate.
- Surviving Sepsis Campaign Adult Guidelines, 2026 — initial MAP targets in septic shock.
- AHA/ACC 2025 High Blood Pressure Guideline — adult systolic and diastolic categories.
- Razminia et al., 2004 — heart-rate limitations of the standard MAP formula.
Last formula and source review: July 23, 2026. The calculator runs in your browser and does not send entered blood pressure values to our server.