# Blood pressure category calculator

> Blood pressure category (AHA/ACC) for a systolic/diastolic reading, from normal to stage 2 and severe hypertension, with pulse pressure and MAP.

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A reading is placed in the AHA/ACC adult categories, set in 2017 and kept unchanged by the 2025 guideline: normal is below 120/80 mmHg, elevated is 120–129 systolic with diastolic below 80, stage 1 hypertension is 130–139 or 80–89, and stage 2 is 140 or higher or 90 or higher. When the two numbers fall in different categories, the higher one applies. Pulse pressure (systolic minus diastolic) and mean arterial pressure (diastolic plus a third of the pulse pressure) are shown too.

People use it to read a home or clinic measurement. The default 118/76 mmHg is normal, with a pulse pressure of 42 and a mean arterial pressure of 90 mmHg; 130/80 would already count as stage 1 hypertension.

The categories describe average blood pressure from repeated, properly taken readings, so one reading cannot diagnose hypertension. Above 180 systolic or 120 diastolic the 2025 guideline calls it severe hypertension, and a hypertensive emergency when there are signs of acute organ damage.

## 输入

- **Systolic (top number)**
- **Diastolic (bottom number)**

## 结果

- Category (AHA/ACC) — 主要结果
- Systolic alone
- Diastolic alone
- Pulse pressure (mmHg)
- Mean arterial pressure (mmHg)

## 公式

$$
\text{category} = \max\big(\text{cat}(\text{SBP}),\ \text{cat}(\text{DBP})\big),\qquad \text{MAP} \approx \text{DBP} + \tfrac{1}{3}(\text{SBP} - \text{DBP})
$$

## 计算示例

### 118/76

- Systolic (top number): 118 mmHg
- Diastolic (bottom number): 76 mmHg
- **Category (AHA/ACC): Normal**
- **Pulse pressure: 42 mmHg**
- **Mean arterial pressure: 90.0 mmHg**
- 核验来源：ACC/AHA 2017 Table 6: <120 and <80 is normal; MAP 76 + 42/3 = 90 (Python fractions)

### Boundary 130/80

- Systolic (top number): 130 mmHg
- Diastolic (bottom number): 80 mmHg
- **Category (AHA/ACC): Stage 1 hypertension**
- **Systolic alone: Stage 1 hypertension**
- **Diastolic alone: Stage 1 hypertension**
- **Mean arterial pressure: 96.7 mmHg**
- 核验来源：ACC/AHA 2017 Table 6: 130–139 or 80–89 is stage 1; MAP 80 + 50/3 = 96.67 (Python fractions)

### Boundary 120/80 takes the diastolic category

- Systolic (top number): 120 mmHg
- Diastolic (bottom number): 80 mmHg
- **Category (AHA/ACC): Stage 1 hypertension**
- **Systolic alone: Elevated**
- 核验来源：ACC/AHA 2017 Table 6: SBP 120 is elevated, DBP 80 is stage 1; readings in two categories take the higher one

### 128/92

- Systolic (top number): 128 mmHg
- Diastolic (bottom number): 92 mmHg
- **Category (AHA/ACC): Stage 2 hypertension**
- **Systolic alone: Elevated**
- **Diastolic alone: Stage 2 hypertension**
- 核验来源：ACC/AHA 2017 Table 6: DBP ≥ 90 is stage 2, which outranks elevated SBP

### 125/79

- Systolic (top number): 125 mmHg
- Diastolic (bottom number): 79 mmHg
- **Category (AHA/ACC): Elevated**
- 核验来源：ACC/AHA 2017 Table 6: 120–129 and <80 is elevated

### 185/100

- Systolic (top number): 185 mmHg
- Diastolic (bottom number): 100 mmHg
- **Category (AHA/ACC): Severe hypertension**
- **Pulse pressure: 85 mmHg**
- 核验来源：2025 AHA/ACC guideline: SBP > 180 and/or DBP > 120 is severe hypertension (the 2017 guideline's hypertensive crisis, §11.2)

## 常见问题

### What is a normal blood pressure?

Below 120 systolic and below 80 diastolic mmHg, in the AHA/ACC classification used by both the 2017 and 2025 US guidelines. A systolic of 120 to 129 with diastolic under 80 is elevated, and 130/80 or higher is hypertension. The cut-offs apply to the average of repeated readings in adults, because any single measurement can run higher or lower than usual.

### What blood pressure is stage 1 and stage 2 hypertension?

Stage 1 is a systolic of 130–139 mmHg or a diastolic of 80–89; stage 2 is a systolic of 140 or more or a diastolic of 90 or more. When the numbers disagree the higher category applies, so 128/92 is stage 2. The 2025 AHA/ACC guideline kept these thresholds and a general treatment goal below 130/80, and uses the PREVENT risk equations with a 7.5 % 10-year risk threshold when weighing medication for stage 1.

### What blood pressure is dangerously high?

Above 180 systolic and/or 120 diastolic mmHg. The 2025 AHA/ACC guideline calls this severe hypertension when there is no sign of acute organ damage, replacing the older term hypertensive urgency, and a hypertensive emergency when there is, which needs monitored hospital treatment. A reading this high together with chest pain, shortness of breath, weakness, or changes in vision or speech is treated as an emergency.

### What are pulse pressure and mean arterial pressure?

Pulse pressure is systolic minus diastolic: 118/76 gives 42 mmHg. Mean arterial pressure, the average pressure across one heartbeat, is commonly estimated as diastolic plus one third of the pulse pressure, which gives 90 mmHg for 118/76. The one-third weighting reflects the heart spending about two thirds of each beat in diastole at resting heart rates, so the estimate is less exact at fast rates.

### How should blood pressure be measured?

With a validated upper-arm device and a cuff of the right size, after a few minutes of quiet rest, seated with back and arm supported, the arm at heart level and no talking. The 2025 AHA/ACC guideline bases diagnosis on averaged readings taken this way, not on a single measurement, so several readings on different days give the value the categories are meant for.

### “Blood pressure category calculator”有多准确？

准确性取决于输入值和方法的假设。十进制运算使用50位有效数字，但估算、数值方法和源数据的精度可能较低；显示时的舍入并不能消除这些限制。 已按独立来源核验的计算示例：7。 例如，“118/76”根据ACC/AHA 2017 Table 6: <120 and <80 is normal; MAP 76 + 42/3 = 90 (Python fractions)进行核验。

### 这种方法出自哪里？

Jones DW, Ferdinand KC, Taler SJ et al. 2025 AHA/ACC/AANP/AAPA/ABC/ACCP/ACPM/AGS/AMA/ASPC/NMA/PCNA/SGIM guideline for the prevention, detection, evaluation and management of high blood pressure in adults. Hypertension 2025;82(10):e212–e316; Whelton PK et al. 2017 ACC/AHA guideline for the prevention, detection, evaluation, and management of high blood pressure in adults. Hypertension 2018;71:e13–e115, Table 6 and §11.2; NHS — Low blood pressure (hypotension): below 90/60 mmHg.

## 来源

- [Jones DW, Ferdinand KC, Taler SJ et al. 2025 AHA/ACC/AANP/AAPA/ABC/ACCP/ACPM/AGS/AMA/ASPC/NMA/PCNA/SGIM guideline for the prevention, detection, evaluation and management of high blood pressure in adults. Hypertension 2025;82(10):e212–e316](https://doi.org/10.1161/HYP.0000000000000249)
- [Whelton PK et al. 2017 ACC/AHA guideline for the prevention, detection, evaluation, and management of high blood pressure in adults. Hypertension 2018;71:e13–e115, Table 6 and §11.2](https://doi.org/10.1161/HYP.0000000000000065)
- [NHS — Low blood pressure (hypotension): below 90/60 mmHg](https://www.nhs.uk/conditions/low-blood-pressure-hypotension/)

_仅供参考，不构成医疗建议。这些公式描述的是人群，并非您的个人情况；根据结果采取行动前，请咨询医务人员。_