Blood Pressure Calculator
Classify a blood pressure reading into AHA categories from systolic and diastolic values.
Pressure when the heart beats
Pressure when the heart rests
Your Reading:
Where You Fall (2017 ACC/AHA Categories)
| Category | Systolic (mmHg) | Diastolic (mmHg) |
|---|---|---|
| Normal | Less than 120 | and Less than 80 |
| Elevated | 120 – 129 | and Less than 80 |
| Hypertension Stage 1 | 130 – 139 | or 80 – 89 |
| Hypertension Stage 2 | 140 or higher | or 90 or higher |
| Hypertensive Crisis | Higher than 180 | and/or Higher than 120 |
What the Numbers Mean
A blood pressure reading is written as two numbers, such as 120/80 mmHg. Each number measures a different part of the cardiac cycle, and both matter when classifying your reading.
Systolic (Top Number)
The systolic pressure is the force against your artery walls when the heart contracts and pumps blood out. It is the higher of the two numbers and tends to rise with age. Elevated systolic pressure is a strong predictor of cardiovascular risk, especially in adults over 50.
Diastolic (Bottom Number)
The diastolic pressure is the force against your artery walls while the heart rests between beats and refills with blood. It is the lower of the two numbers. A reading is classified by whichever number places it in the higher category.
The 2017 ACC/AHA Blood Pressure Categories
In 2017 the American College of Cardiology and the American Heart Association lowered the threshold for hypertension. Your category is determined by the higher of the two numbers. For example, a reading of 135/85 falls into Stage 1 because the systolic value reaches the Stage 1 range, even though the diastolic value alone would too.
| Category | Systolic (mmHg) | Diastolic (mmHg) |
|---|---|---|
| Normal | Less than 120 | and Less than 80 |
| Elevated | 120 – 129 | and Less than 80 |
| Hypertension Stage 1 | 130 – 139 | or 80 – 89 |
| Hypertension Stage 2 | 140 or higher | or 90 or higher |
| Hypertensive Crisis | Higher than 180 | and/or Higher than 120 |
When to Seek Care
- A single high reading does not mean you have hypertension. Diagnosis requires multiple readings on separate occasions, confirmed by a healthcare professional.
- If your reading is in the Elevated or Stage 1 range, discuss lifestyle changes and monitoring with your doctor.
- A reading in Stage 2 usually warrants prompt medical attention and may require medication.
- A Hypertensive Crisis (above 180 systolic and/or above 120 diastolic) is a medical emergency. If you also have chest pain, shortness of breath, weakness, vision changes, or difficulty speaking, call emergency services immediately.
Note: This calculator classifies a single blood pressure reading using the 2017 ACC/AHA guideline. It is an educational tool and does not diagnose hypertension or any medical condition. Blood pressure varies throughout the day and can be affected by stress, caffeine, activity, and measurement technique. Always consult a qualified healthcare professional for diagnosis and treatment.