Blood Pressure Category Calculator
Classify a reading using the standard AHA blood-pressure stages.
Input sheet
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A blood-pressure reading is two numbers — systolic over diastolic — and where they fall determines your category. This tool classifies a single reading using the standard American Heart Association stages so you can see whether it lands in the normal, elevated, or hypertensive range.
How it works
Stages follow AHA guidelines: Normal <120/<80, Elevated 120–129/<80, Stage 1 130–139 or 80–89, Stage 2 ≥140 or ≥90, Crisis ≥180 or ≥120.
The AHA stages are: Normal below 120/80; Elevated when systolic is 120–129 and diastolic is under 80; Stage 1 hypertension at 130–139 systolic or 80–89 diastolic; Stage 2 at 140 or higher systolic or 90 or higher diastolic; and Hypertensive crisis at 180 or higher systolic or 120 or higher diastolic.
When the two numbers fall in different stages, the higher stage wins. A reading like 135/75 is Stage 1 on the systolic number even though the diastolic number alone would be Normal. This is a single-reading classifier and an educational tool, not a diagnosis.
Take the higher of the two stages: Normal (<120 and <80), Elevated (120–129 and <80), Stage 1 (130–139 or 80–89), Stage 2 (≥140 or ≥90), Crisis (≥180 or ≥120).
Worked examples
A reading of 118/76. → Normal.
Systolic 118 is under 120 and diastolic 76 is under 80, so both numbers sit in the Normal range.
A reading of 135/85. → Stage 1 hypertension.
Systolic 135 falls in the 130–139 Stage 1 band and diastolic 85 falls in the 80–89 Stage 1 band; the reading is Stage 1.
Tips & gotchas
- A single high reading isn't a diagnosis. Hypertension is confirmed from multiple readings on separate occasions, so don't panic over one number.
- Measure seated with your back supported and feet flat, arm at heart level, after resting quietly for about five minutes. Poor technique inflates readings.
- Avoid caffeine, exercise, and smoking for at least 30 minutes before measuring, and empty your bladder — all of these can temporarily raise the numbers.
- A hypertensive-crisis reading (180 or higher over 120 or higher) with symptoms like chest pain, shortness of breath, or vision changes is a medical emergency — seek care immediately.
FAQ
Which number sets the category?
Whichever number — systolic or diastolic — lands in the higher stage.
What does 'Elevated' mean if it isn't hypertension yet?
Elevated is a warning band: systolic 120–129 with diastolic under 80. It signals a rising trend and a good time for lifestyle changes before it progresses to Stage 1.
Can my category be different at home versus at the doctor's office?
Yes. 'White-coat' readings can run higher in a clinical setting, while some people have higher readings only at home. That's why averaging multiple readings across settings is recommended.
Does this calculator account for my age or medications?
No. It applies the standard adult AHA thresholds to the numbers you enter. Age, pregnancy, and medications can change target ranges, so discuss your specific goals with a clinician.
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