Blood Pressure Category Calculator
What your systolic and diastolic reading means, on the ACC/AHA categories.
A blood pressure reading is two numbers: the pressure when your heart beats, and the pressure between beats. This tells you which category a reading falls into and what the usual next step is — it is not a diagnosis, which needs several readings on different days.
How this is worked out
The 2017 ACC/AHA categories are: normal below 120/80; elevated 120–129 systolic with diastolic under 80; stage 1 hypertension 130–139 or 80–89; stage 2 hypertension 140 or above, or 90 or above; and hypertensive crisis above 180 or above 120. When the two numbers fall in different categories, the higher category is the one that counts.
Not every guideline draws the lines in the same place — the European Society of Cardiology and several national guidelines still start hypertension at 140/90 for the clinic setting. A reading also depends heavily on how it was taken: sit quietly for five minutes, back supported, feet flat, arm at heart height, no caffeine or exercise for half an hour, and take two readings a minute apart.
A reading above 180/120 needs attention now. With symptoms such as chest pain, breathlessness, weakness, difficulty speaking or visual changes, treat it as an emergency and call for help rather than repeating the measurement.
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Common questions
Which number matters more?
Both, and whichever is higher sets your category. Systolic pressure tends to predict risk better after about age 50; diastolic carries more weight in younger adults.
Why is my reading higher at the clinic?
White coat hypertension is common. Home readings over several days, or a 24-hour ambulatory monitor, give a truer picture, which is why doctors often ask for a home diary before starting treatment.