Mean Arterial Pressure (MAP): Formula and What It Means

Mean arterial pressure (MAP) is the average pressure in your arteries across one full heartbeat, and it's calculated as diastolic + (systolic − diastolic) / 3. It leans on the diastolic number more heavily than the systolic one, because your heart spends more of each cycle relaxed between beats than it does contracting. If you log blood pressure readings, you may see MAP shown as a small sparkline alongside your systolic and diastolic trend — it's a calculated number, not a separate measurement.

What Is Mean Arterial Pressure?

Every heartbeat has two phases: systole, when the heart contracts and pushes blood out, and diastole, when it relaxes and refills. Systolic and diastolic pressure capture the two extremes of that cycle, but neither one describes the average pressure your arteries actually experience over time. Mean arterial pressure fills that gap. It's a single number that approximates the average pressure pushing blood through your arterial system across a full cardiac cycle, which is why it shows up in clinical settings — particularly ones where perfusion of organs like the kidneys and brain is a concern — more than it shows up in routine home readings.

For most people tracking blood pressure at home, MAP is a useful extra data point rather than a number to manage on its own. Your systolic and diastolic readings, and the pattern they form over weeks, remain the primary numbers your clinician will look at.

The MAP Formula

The standard formula for estimating mean arterial pressure from a single cuff reading is:

MAP = diastolic + (systolic − diastolic) / 3

Written out, that means you take the gap between your systolic and diastolic numbers (this gap is also called pulse pressure), divide it by three, and add the result back to your diastolic number. The reason diastolic is weighted more heavily is simple: at a typical resting heart rate, diastole (the relaxed phase) lasts roughly twice as long as systole (the contraction phase) within each cycle. Weighting the formula toward diastolic reflects that a resting heart spends more time in that phase than in the contraction phase.

How to Calculate MAP: Worked Examples

The easiest way to see how the formula behaves is to run it against a few real-looking readings. The table below shows four example readings, the pulse pressure (systolic minus diastolic) for each, and the resulting MAP:

Notice that two readings with a similar systolic number, like 132/84 and 150/95, can produce noticeably different MAP values once the diastolic number and pulse pressure shift. That's the formula doing what it's designed to do: reflecting the whole cycle rather than just the peak.

Why Diastolic Counts More Than Systolic in This Formula

It can look odd at first that diastolic pressure — the lower of your two numbers — gets more weight in the MAP formula than systolic, the higher one. The explanation is about time, not importance. Because diastole occupies roughly two-thirds of a resting cardiac cycle and systole occupies roughly one-third, an average across the full cycle sits closer to the diastolic value than to the systolic peak. The formula's structure — diastolic plus one-third of the gap, rather than a simple average of the two numbers — is a shorthand way of encoding that timing.

This is also why MAP isn't just "the number in between" your systolic and diastolic readings. A simple average of 132 and 84 would be 108; the MAP formula instead gives 100, precisely because it weights diastolic more heavily.

What MAP Can — and Can't — Tell You

MAP is a calculated estimate, not a diagnosis, and it isn't paired with a public target range the way systolic and diastolic categories are. There is no standard "normal MAP" number presented here, and we won't suggest one — if a clinician has asked you to pay attention to your MAP for a specific reason, they are the right person to set the range that applies to your situation, not a generic chart. This mirrors how the number works clinically: it's typically interpreted by a professional alongside other measurements and the reason it's being watched in the first place, rather than read on its own.

It's also worth remembering that a single reading — whether you're looking at the systolic, diastolic or the derived MAP number — cannot diagnose hypertension. A single reading cannot diagnose hypertension; classification always depends on a pattern of repeated, correctly taken measurements over time, not any one number in isolation.

Regardless of what a given reading's MAP works out to, one separate safety threshold still applies: systolic over 180 or diastolic over 120 calls for immediate attention. If you or someone near you gets a reading in that range — especially with symptoms like chest pain, shortness of breath, a severe headache or sudden vision changes — call emergency services right away rather than waiting to see how the next reading looks.

Seeing MAP Alongside Your Other Numbers

BPal calculates MAP automatically from the systolic and diastolic numbers you log, so you don't need to work through the formula by hand. It appears as a dedicated sparkline next to your other trend lines, letting you see how it moves over the same 7-day, 30-day or longer ranges as your regular readings. When you generate a PDF report to share with a doctor, MAP can be included as an optional field, and the report's own definitions page explains what it is and how it's calculated — useful context for whoever is reading the report alongside you. For a broader walkthrough of the trend view itself, see our guide to blood pressure trends and charts, and for how MAP shows up in a shareable report, see the guide to building a report for your doctor.

Frequently Asked Questions

What is a good MAP number?

There isn't a single public target we can responsibly give here, and the app deliberately doesn't suggest one either. MAP is typically interpreted by a clinician in the context of why it's being measured in the first place. If your doctor has asked you to watch your MAP, ask them what range is relevant to your situation.

Is MAP more accurate than systolic and diastolic pressure?

Not more accurate — different. Systolic and diastolic describe the two extremes of your cardiac cycle, while MAP estimates the average across the whole cycle. Clinicians use MAP for particular purposes, such as assessing perfusion pressure, but it doesn't replace the systolic and diastolic categories used for everyday blood pressure classification.

Can I calculate MAP from a home blood pressure monitor reading?

Yes. Any systolic and diastolic pair from a standard home monitor can be run through the formula: diastolic + (systolic − diastolic) / 3. BPal does this automatically for every reading you log, since it's a straightforward calculation based on the two numbers you already record.

To see how MAP relates to the gap between your two numbers, read our piece on pulse pressure. If you want the full picture of how readings are categorized in the first place, see our blood pressure chart guide, and if pulse and blood pressure trends together are new territory, blood pressure vs heart rate explains how the two relate.