How to use Blood Pressure Category Checker
This blood pressure category checker takes your two readings — systolic (the higher number) and diastolic (the lower number) — and tells you which category they fall into under the American College of Cardiology / American Heart Association (ACC/AHA) 2017 guidelines. The categories run from normal through elevated and two stages of hypertension up to a hypertensive crisis. Seeing where a reading sits, alongside the full reference chart, helps you understand a number your doctor or home monitor gives you. It is an information tool, not a diagnosis, and a single reading should never be read in isolation.
- Enter your systolic (top) number in mmHg.
- Enter your diastolic (bottom) number in mmHg.
- Select check to see your category.
- Read the category and general guidance.
- Compare against the full chart shown below.
Your data never leaves your device — 100% private processing.
Understanding the categories
Blood pressure is written as systolic over diastolic in millimetres of mercury (mmHg). Systolic is the pressure when the heart beats; diastolic is the pressure when it rests between beats. Under the ACC/AHA 2017 guideline, normal is below 120 and below 80. Elevated is a systolic of 120–129 with a diastolic still below 80 — a warning zone rather than hypertension. Stage 1 hypertension begins at 130 systolic or 80 diastolic, and Stage 2 at 140 systolic or 90 diastolic. A reading above 180 systolic and/or above 120 diastolic is a hypertensive crisis that needs prompt medical attention. A key rule: when your two numbers fall into different categories, the higher category applies, so 135/75 is classified as Stage 1 on the systolic value alone.
| Category | Systolic | Diastolic |
|---|---|---|
| Normal | Below 120 | and below 80 |
| Elevated | 120–129 | and below 80 |
| Stage 1 | 130–139 | or 80–89 |
| Stage 2 | 140 or higher | or 90 or higher |
| Crisis | Above 180 | and/or above 120 |
Why one reading is not enough
Blood pressure naturally rises and falls through the day in response to activity, stress, caffeine, posture and even the simple act of being measured — the so-called white-coat effect can push clinic readings up. For that reason, a diagnosis of hypertension is never based on a single number; clinicians look at several readings taken on different occasions, often including measurements you take at home. To get a reliable reading, sit quietly for five minutes first, keep your feet flat and your arm supported at heart height, avoid caffeine and exercise beforehand, and take two or three readings a minute apart. If your numbers regularly fall into the elevated or hypertension ranges — or if you ever see crisis-level values — speak to a healthcare professional. This checker is here to help you interpret the numbers, not to replace that conversation.
Worked examples
Healthy reading
Inputs: 118/76 mmHg
Result: Normal
Stage 1
Inputs: 135/85 mmHg
Result: Hypertension Stage 1
Glossary
- Systolic
- The higher number — pressure in the arteries when the heart beats.
- Diastolic
- The lower number — pressure when the heart rests between beats.
- mmHg
- Millimetres of mercury, the unit used to measure blood pressure.
- Hypertension
- Persistently high blood pressure, classified into stages 1 and 2.
- Hypertensive crisis
- A reading above 180/120 mmHg that needs urgent attention.
Related reading
Frequently Asked Questions
Why use Blood Pressure Category Checker?
- Classifies a reading using ACC/AHA 2017 categories
- Shows both numbers and the resulting category clearly
- Includes the full reference chart for context
- Explains what each category generally implies
- Runs in your browser — your readings stay private
Common use cases
- Understand a reading from a home blood pressure monitor
- See which category a clinic reading falls into
- Learn the ACC/AHA thresholds at a glance
- Track whether lifestyle changes move your category
- Explain blood pressure categories to a family member
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