Your mean arterial pressure from a blood pressure reading, and what the range means.
Updated Sep 2026Fill in the fields and press Calculate. Every range comes from the sources listed under the tool.
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Sources
- Optimal Calculation of Mean Pressure From Pulse Pressure (American Journal of Hypertension, 2023) PubMed Central (PMC)
- Physiology, Mean Arterial Pressure - StatPearls - NCBI Bookshelf NIH National Library of Medicine (NCBI Bookshelf)
- High Blood Pressure - What Is High Blood Pressure? | NHLBI, NIH NIH National Heart, Lung, and Blood Institute
- Low blood pressure: MedlinePlus Medical Encyclopedia MedlinePlus
What This MAP Calculator Works Out
This mean arterial pressure calculator turns the two numbers of a blood pressure reading into one: the average pressure in your arteries across a whole heartbeat. A reading of 120 over 80 says the pressure peaks at 120 mmHg when the heart squeezes and falls to 80 between beats; the mean arterial pressure, MAP, is where the average sits, and it is the figure clinicians watch because it is the pressure that actually pushes blood through the organs.
The standard formula is the bottom number plus one third of the gap between the two, so 120 over 80 gives 80 plus a third of 40, which is 93. The calculator also shows the pulse pressure, the gap itself, and the blood pressure category of the reading under the American Heart Association’s rules, so the two ways of reading one measurement sit side by side.
- Between the bottom and the top number
- The mean arterial pressure
Mean Arterial Pressure Ranges
| MAP (mmHg) | Range | What it means |
|---|---|---|
| Under 70 | Below normal | Under 65 is the floor clinical guidelines set for patients being monitored; from a home reading it usually means low blood pressure |
| 70 to 100 | Normal | The range that keeps the brain, heart and kidneys supplied |
| Over 100 | Above normal | Goes with high blood pressure; a run of rested readings over several days is the next step |
The 70 to 100 range is the one a 2023 review in the American Journal of Hypertension gives as generally understood for adults. The floor matters most in hospital: sepsis guidelines target a MAP of at least 65 mmHg because below it the organs stop being perfused, and severe pre-eclampsia protocols treat from 125. For a home reading, MAP is a second way of reading the same two numbers rather than a separate diagnosis, and the blood pressure category still applies: 120 over 80 has a normal MAP of 93 and is stage 1 high blood pressure on the diastolic number under the 2017 categories.
Why the Mean Is Not the Midpoint
The midpoint of 120 and 80 would be 100, but the heart spends about twice as long relaxing as squeezing, so the pressure sits near the bottom number for most of each beat and the average lands a third of the way up, not halfway. That is the whole reason for the one-third rule, which dates from 1960. Measured against the true mean from a continuous pressure trace, the standard formula runs about 2 mmHg low on average; a later version that uses 0.412 of the gap instead of a third runs about 1 mmHg high and matches the trace most closely, so the calculator shows that figure too. At a high heart rate the heart spends less time relaxing and both estimates drift low, which is one reason MAP in intensive care is measured directly rather than calculated.
For the reading itself, the blood pressure checker places it in its category and the page on what is a normal blood pressure puts blood pressure beside resting pulse, A1C and caffeine. The heart rate zone calculator covers the other side of the heart’s work.
Frequently Asked Questions
What is a normal mean arterial pressure?
70 to 100 mmHg. A reading of 120 over 80 gives a MAP of 93, which is in the middle of the range. Below 65 is the floor set for patients being monitored in hospital, and above 100 goes with high blood pressure.
How do you calculate mean arterial pressure?
Take the bottom number and add one third of the difference between the two: MAP = diastolic + (systolic minus diastolic) divided by 3. For 130 over 85 that is 85 plus 15, which is 100. The calculator does the arithmetic and shows the 0.412 version beside it.
Why is MAP closer to the diastolic number?
Because the heart spends about two thirds of each beat relaxing, so the pressure sits near the bottom number for longer than near the top. The average over the beat is therefore a third of the way up from the bottom, not halfway.
Is MAP more important than blood pressure?
They are two readings of the same measurement. MAP is what clinicians monitor in intensive care, surgery and pregnancy because it is the pressure that perfuses the organs. For everyday health the blood pressure categories are the ones the guidelines are written in, and a MAP from a home cuff is informational rather than diagnostic.
What MAP is too low?
Guidelines for critically ill patients set the floor at 65 mmHg. At home, a MAP under 70 usually reflects low blood pressure; if it comes with dizziness, fainting, blurred vision or confusion, seek medical advice.
Sources
- Optimal Calculation of Mean Pressure From Pulse Pressure · American Journal of Hypertension, 2023 (PMC)
- Physiology, Mean Arterial Pressure · StatPearls, NCBI Bookshelf (NIH)
- High Blood Pressure: What Is High Blood Pressure? · NIH National Heart, Lung, and Blood Institute
- Low blood pressure · MedlinePlus Medical Encyclopedia (NIH)
This calculator is for general information only and is not a substitute for professional medical advice, diagnosis, or treatment.