Blood Pressure Calculator
Enter your systolic and diastolic numbers to see which American Heart Association category the reading falls into, plus your mean arterial pressure (MAP) and pulse pressure. You can also average several readings. For information only, not a diagnosis.
How to use the Blood Pressure Calculator
- Measure your blood pressure after sitting quietly for 5 minutes, arm supported at heart level.
- Enter the systolic and diastolic numbers (and pulse if you have it), or switch to averaging and paste several readings.
- Read your category and what the numbers mean.
- Check MAP and pulse pressure and the reference table.
- Share the results with your doctor; copy them with one click.
Blood pressure chart (AHA/ACC 2017)
| Category | Systolic (mmHg) | Diastolic (mmHg) | |
|---|---|---|---|
| Normal | less than 120 | and | less than 80 |
| Elevated | 120–129 | and | less than 80 |
| Hypertension stage 1 | 130–139 | or | 80–89 |
| Hypertension stage 2 | 140 or higher | or | 90 or higher |
| Hypertensive crisis | higher than 180 | and/or | higher than 120 |
These categories are for adults. Children and teens are assessed with percentile charts based on age, sex and height. Other organizations (for example European and UK guidelines) use slightly different thresholds, such as 140/90 for clinic-measured hypertension.
Formulas used
- Mean arterial pressure: MAP ≈ DBP + (SBP − DBP) ÷ 3. Example: 128/82 → 82 + 46 ÷ 3 = 97.3 mmHg.
- Pulse pressure: PP = SBP − DBP. Example: 128 − 82 = 46 mmHg.
- Average of readings: add the systolic values and divide by the number of readings, and do the same for diastolic.
Frequently asked questions
What are the blood pressure categories?
The 2017 American Heart Association / American College of Cardiology guideline uses: normal under 120/80; elevated 120–129 systolic with diastolic under 80; stage 1 hypertension 130–139 or 80–89; stage 2 hypertension 140 or higher or 90 or higher; and hypertensive crisis above 180 and/or above 120 mmHg.
Which number counts if systolic and diastolic fall in different categories?
The higher category applies. For example, 125/85 is stage 1 hypertension because the diastolic number of 85 falls in the stage 1 range, even though 125 alone would be elevated.
How is mean arterial pressure calculated?
A common estimate is MAP = diastolic + (systolic − diastolic) ÷ 3, because the heart spends about two thirds of each beat relaxing. For 120/80 that gives 80 + 40 ÷ 3 ≈ 93 mmHg.
What is pulse pressure?
Pulse pressure is the difference between the systolic and diastolic numbers. For 120/80 it is 40 mmHg. A consistently wide pulse pressure, often over 60 mmHg in older adults, can be associated with stiffer arteries.
Can one reading tell me if I have high blood pressure?
No. Blood pressure varies through the day and with stress, caffeine, exercise and how you measure it. Guidelines base a diagnosis on the average of two or more readings taken on two or more occasions, ideally with home or ambulatory monitoring.
How should I measure blood pressure at home?
Avoid caffeine, exercise and smoking for 30 minutes, empty your bladder, sit with your back supported and feet flat for 5 minutes, rest your arm at heart level and use a validated cuff of the right size. Take two readings a minute apart and record both.
Is this calculator a medical device?
No. It classifies numbers you enter using published categories and is for information only. It cannot diagnose or treat any condition. Talk to a healthcare professional about your readings.