check your reading against AHA blood pressure categories
Your reading
Your Category
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A reading this high can signal a hypertensive crisis. If you also have chest pain, shortness of breath, severe headache, or vision changes, seek emergency care immediately. Otherwise, contact a doctor promptly to confirm the reading.
Systolic (top number)
Diastolic (bottom number)
How this calculator works
Blood pressure is measured with two numbers: systolic (pressure when your heart beats) over diastolic (pressure when your heart rests between beats). This calculator compares both numbers against the American Heart Association's standard categories and reports whichever category your reading falls into — using the higher category if systolic and diastolic point to different ones, since that's the standard clinical convention.
Blood pressure category chart
Category
Systolic
Diastolic
Low (Hypotension)
Below 90
or
Below 60
Normal
Below 120
and
Below 80
Elevated
120–129
and
Below 80
High BP — Stage 1
130–139
or
80–89
High BP — Stage 2
140+
or
90+
Hypertensive Crisis
Over 180
and/or
Over 120
Frequently asked questions
A normal reading is below 120 systolic and below 80 diastolic, often written as "under 120/80." This reflects healthy blood flow with no added strain on your heart and arteries.
Systolic (the top number) measures pressure in your arteries when your heart contracts and pumps blood. Diastolic (the bottom number) measures pressure when your heart relaxes between beats. Both matter, but systolic tends to be a stronger predictor of cardiovascular risk after age 50.
Common contributors include excess sodium intake, being overweight, low physical activity, smoking, high alcohol use, chronic stress, certain medications, and genetics. In many cases, several factors combine rather than one single cause.
Yes, significantly. It's typically lowest during sleep, rises in the morning, and fluctuates with activity, stress, caffeine, and meals. A single reading is a snapshot, not the full picture — doctors often look at readings taken over several days.
If your reading is over 180 systolic or over 120 diastolic, especially alongside chest pain, shortness of breath, severe headache, confusion, or vision changes, seek emergency care immediately — this can indicate a hypertensive crisis.
Commonly recommended approaches include reducing sodium intake, maintaining a healthy weight, regular physical activity, limiting alcohol, managing stress, and not smoking. Any significant or sustained change in blood pressure should still be discussed with a doctor, especially before stopping or changing medication.
Not medical advice: A single home reading can be affected by stress, posture, caffeine, or measurement technique. If you get a reading outside the normal range, take another reading after resting a few minutes, and talk to a doctor about a pattern of readings rather than one measurement alone.