Blood Pressure Classifier
Enter your systolic and diastolic blood pressure to see your category under the international (ESH/ISH) guidelines, plus pulse pressure and mean arterial pressure.
Inputs
Results
Understanding blood pressure
Blood pressure is written as two numbers separated by a slash, e.g. 120/80 mmHg:
- Systolic (top number): the peak pressure when the heart contracts and pumps blood into the arteries
- Diastolic (bottom number): the pressure when the heart relaxes between beats
Both are measured in millimetres of mercury (mmHg).
International (ESH/ISH) classification
This calculator's default categories follow the international guidelines used across most of the world — the European Society of Hypertension (ESH/ESC) and the International Society of Hypertension (ISH), which define hypertension as a reading of 140/90 mmHg or higher:
| Category | Systolic (mmHg) | Diastolic (mmHg) |
|---|---|---|
| Optimal | < 120 | and < 80 |
| Normal | 120–129 | and 80–84 |
| High–normal | 130–139 | or 85–89 |
| Grade 1 hypertension | 140–159 | or 90–99 |
| Grade 2 hypertension | 160–179 | or 100–109 |
| Grade 3 hypertension | ≥ 180 | or ≥ 110 |
When the systolic and diastolic numbers fall into different categories, the guideline assigns the higher (more severe) category. This calculator follows that rule: it classifies each number independently and reports whichever category is worse. So a reading of 115/95 — normal systolic but a Grade 1 diastolic — is classified as Grade 1 hypertension, not normal. This matters for younger adults, in whom isolated diastolic hypertension is more common.
National guidelines differ
There is no single worldwide blood-pressure standard. The threshold for diagnosing hypertension is 140/90 mmHg under the international, Japanese, and Korean guidelines, but 130/80 mmHg under the 2017 US (ACC/AHA) and 2022 Taiwan (TSOC/THS) guidelines. This calculator selects the appropriate scheme automatically based on your language, so the category you see reflects the standard used by clinicians in your region:
| Language / region | Guideline | Hypertension from |
|---|---|---|
| English & others (default) | ESH/ISH | 140/90 |
| 日本語 (Japan) | JSH 2019 | 140/90 |
| 한국어 (Korea) | KSH 2018 | 140/90 |
| 繁體中文 (Taiwan) | TSOC/THS 2022 | 130/80 |
United States (?region=us) | ACC/AHA 2017 | 130/80 |
Because the cut-offs differ, the same reading can land in differently named categories depending on which guideline applies. Always interpret your numbers against the standard your own doctor uses.
Pulse pressure
Pulse pressure is the difference between the systolic and diastolic readings:
A normal pulse pressure is roughly 40 mmHg. Values consistently above 60 mmHg may indicate arterial stiffness, a risk factor for heart disease and stroke. A very low pulse pressure (below 25 mmHg) can indicate heart failure or shock.
Mean arterial pressure
Mean arterial pressure (MAP) is the average blood pressure throughout the cardiac cycle. Because the heart spends more time in diastole (relaxation) than systole (contraction), MAP is weighted toward the diastolic value:
This is a simplified estimate. The precise value requires integration of the arterial waveform under invasive monitoring, but the formula above is accurate to within a few mmHg for most resting adults.
MAP represents the effective perfusion pressure that drives blood through the tissues. A MAP below 60 mmHg indicates that organs may not be receiving adequate blood flow, and ICU protocols typically target a minimum MAP of 65 mmHg.
Frequently Asked Questions (FAQ)
What do the systolic and diastolic numbers mean?
Blood pressure is written as systolic/diastolic, e.g. 120/80 mmHg. Systolic (the top number) is the pressure when your heart beats and pumps blood. Diastolic (the bottom number) is the pressure when the heart rests between beats. Both numbers matter; high readings in either can indicate cardiovascular risk.
When is blood pressure dangerously high?
Under the international (ESH/ISH) guidelines, a systolic reading of 180 mmHg or higher and/or a diastolic of 110 mmHg or higher is Grade 3 hypertension — the most severe category. At this level, prompt medical attention is warranted, especially if accompanied by symptoms such as severe headache, chest pain, shortness of breath, or blurred vision. Grade 1 hypertension (≥ 140/90) already warrants medical review and lifestyle or medication intervention.
Why is mean arterial pressure (MAP) clinically important?
MAP represents the effective perfusion pressure that drives blood through the tissues. Clinicians use MAP to assess whether organs are receiving adequate blood flow. A MAP below 60 mmHg is a critical threshold — below this, the kidneys, brain, and heart may not receive sufficient oxygen. ICU teams continuously monitor MAP and typically target a minimum of 65 mmHg in critically ill patients.
What is white-coat hypertension?
White-coat hypertension is a pattern where blood pressure measured in a clinical setting is elevated but is normal during home monitoring — often due to anxiety about medical visits. It affects roughly 15–30% of people diagnosed with hypertension in clinics.
Home monitoring over several days gives a more representative picture than a single clinical reading. Some people have the opposite pattern ('masked hypertension'), with normal clinic readings but high readings at home.
My reading is slightly elevated — do I have hypertension?
A single elevated reading does not diagnose hypertension. Blood pressure varies throughout the day, with activity, stress, temperature, and caffeine. Diagnosis requires multiple readings over time, taken under consistent conditions. Home monitoring over several days or weeks gives a much more reliable picture than a single clinic visit.
What is a normal blood pressure for adults?
Under the international (ESH/ISH) guidelines, optimal blood pressure is below 120/80 mmHg, and readings up to 129/84 are still classed as normal. There is no universal "ideal" — lower is generally better within the normal range, provided you have no symptoms of low blood pressure (dizziness, fainting).
Does diastolic pressure matter less than systolic?
For older adults (over 50), systolic pressure is generally the stronger predictor of cardiovascular risk. For younger adults, elevated diastolic pressure is more concerning. In clinical practice, both numbers are evaluated together; this calculator follows the guideline convention of reporting the higher-classified number when systolic and diastolic point to different categories.
Disclaimer
This classifier uses the international (ESH/ISH) office blood-pressure categories. National guidelines differ — the US (ACC/AHA), Japan (JSH), Korea (KSH), and Taiwan (TSOC/THS) each use their own thresholds, and the calculator selects them automatically by language. Blood pressure should always be interpreted by a qualified healthcare provider in the context of your complete health history.
Recommended Next
BMI Calculator
Compute Body Mass Index from height and weight, with WHO, WHO Asia-Pacific, and JASSO classification tables.