Blood Pressure Calculator

1. Find the top number (systolic). When your heart beats and pushes blood through your arteries, it creates peak pressure. This is your systolic reading. It is always the larger number in a reading like 120/80.
2. Find the bottom number (diastolic). Between beats, your heart rests and pressure drops to its lowest point. This is your diastolic reading. In 120/80, diastolic is 80.
3. Enter both numbers. Type your systolic reading in the top field and diastolic in the bottom field. Both are in millimeters of mercury (mmHg).
4. Read your category. The calculator shows your AHA blood pressure category, pulse pressure, and mean arterial pressure (MAP) instantly.
5. Check the recommendations. Each category has an action recommendation. If you are in the Hypertensive Crisis range (180 or above systolic, or 120 or above diastolic), seek emergency care immediately.

Blood pressure is recorded as two numbers separated by a slash: systolic over diastolic (e.g., 120/80 mmHg). The calculator uses these two values to determine your AHA category and compute two additional clinically useful measures.

Pulse Pressure

Pulse Pressure = Systolic – Diastolic

Example: 120 – 80 = 40 mmHg (normal range: 40 – 60 mmHg)

Pulse pressure reflects how hard your heart works with each beat. A pulse pressure above 60 mmHg (wide pulse pressure) can indicate arterial stiffness, a risk factor for cardiovascular disease. A narrow pulse pressure below 25 mmHg may indicate reduced cardiac output.

Mean Arterial Pressure (MAP)

MAP = Diastolic + (Pulse Pressure / 3)
    = Diastolic + (Systolic – Diastolic) / 3

Example: 80 + (120 – 80) / 3 = 80 + 13.3 = 93 mmHg

MAP represents the average pressure in your arteries throughout one complete cardiac cycle. It is weighted toward diastolic pressure because the heart spends more time in diastole (relaxation) than systole (contraction). A MAP of 70 to 100 mmHg is considered normal for healthy adults. Values below 60 mmHg indicate inadequate perfusion of vital organs.

AHA Category Logic: The 2017 American Heart Association guidelines classify blood pressure using whichever number (systolic or diastolic) places the reading in the highest category. So a reading of 135/91 is Stage 2 (because 91 diastolic meets that threshold) even though the systolic of 135 would only reach Stage 1.