Medical & Clinical
Blood Pressure Calculator
Two numbers decide a lifetime of risk. Enter your latest reading and see exactly which ACC/AHA category you fall into.
Blood pressure is recorded as systolic over diastolic (mmHg). The ACC/AHA categories: normal below 120/80, elevated 120–129 and under 80, stage 1 hypertension 130–139 or 80–89, and stage 2 at 140/90 or above. Interpretation belongs to your clinician — use these numbers to ask better questions.
Normal: < 120/80 mmHg.
Stage 1: 130–139 / 80–89.
One reading is not a diagnosis — average 2–3.
Calculate Your Blood Pressure
Your Reading
What Is Blood Pressure?
Blood pressure is the force of blood against artery walls, measured as systolic (during heartbeats) over diastolic (between beats). The ACC/AHA 2017 guideline defines the categories used in U.S. clinical practice.
The calculator also derives mean arterial pressure (the average driving pressure perfusing your organs) and pulse pressure (a window into arterial stiffness).
How It Is Calculated
MAP = (SBP + 2 × DBP) ÷ 3
Pulse pressure = SBP − DBP
Example: Example: 128/82 → Stage 1 hypertension; MAP ≈ 97 mmHg
ACC/AHA 2017 blood pressure categories
| Category | Systolic | Diastolic |
|---|---|---|
| Normal | < 120 | and < 80 |
| Elevated | 120–129 | and < 80 |
| Stage 1 hypertension | 130–139 | or 80–89 |
| Stage 2 hypertension | ≥ 140 | or ≥ 90 |
| Hypertensive crisis | > 180 | and/or > 120 |
Limitations
- Measure seated, arm at heart level, after 5 quiet minutes — and average 2–3 readings.
- White-coat and masked hypertension are real: home monitoring adds context.
- One reading never diagnoses hypertension; trends across visits do.
How to Measure Blood Pressure Correctly
- Sit quietly. Sit for 5 minutes with feet flat, back supported, and legs uncrossed before measuring.
- Position the cuff. Place the cuff on your bare upper arm, 2–3 cm above the elbow, with the arm supported at heart level.
- Take multiple readings. Take 2–3 readings one minute apart and average them — the first reading is often the highest.
- Record and repeat. Measure at the same time daily and share the trend with your clinician.
Sources & Review
References used for this calculator’s formulas and thresholds:
Blood Pressure FAQ
What is normal blood pressure?
Below 120/80 mmHg. Readings from 120–129 systolic with normal diastolic are 'elevated' — a warning, not hypertension.
When is blood pressure dangerously high?
180/120 or above is a hypertensive crisis. With chest pain, shortness of breath, or confusion, seek emergency care.
How do I get an accurate reading?
Sit quietly for 5 minutes, feet flat, arm supported at heart level, no caffeine or exercise for 30 minutes — and average 2–3 readings.
Can blood pressure be lowered without medication?
Often yes, especially at elevated/stage 1 levels — weight loss, DASH-style eating, sodium under 2,300 mg, activity, and less alcohol each move the numbers.
Important disclaimer: Results are educational estimates, not a substitute for professional medical advice. Discuss your results with a qualified professional before making decisions.