Blood Pressure Checker
Check your blood pressure category and understand what your numbers mean — AHA 2017 guidelines.
About Blood Pressure
Blood pressure is measured as systolic (when the heart beats) over diastolic (when the heart rests) in mmHg. The American Heart Association 2017 guidelines define five categories from Normal to Hypertensive Crisis.
Accuracy This tool applies the 2017 AHA guideline thresholds directly to your entered values — it is only as accurate as the reading you provide. A single home reading can vary by 5–10 mmHg due to stress, posture, or timing. For clinical accuracy, take the average of 2–3 readings on separate occasions.
AHA 2017 Blood Pressure Categories
| Category | Systolic | Diastolic |
|---|---|---|
| Normal | < 120 | < 80 |
| Elevated | 120–129 | < 80 |
| High BP — Stage 1 | 130–139 | 80–89 |
| High BP — Stage 2 | ≥ 140 | ≥ 90 |
| Hypertensive Crisis | > 180 | > 120 |
What to do with your result
- If your result is Elevated or higher, measure at the same time daily for one week and record the readings to identify patterns before seeing a doctor.
- Start the DASH diet — rich in fruits, vegetables, and low-fat dairy — which can lower systolic BP by 8–11 mmHg.
- Reduce sodium to under 2,300 mg/day (1 tsp salt) and aim for 150 minutes of moderate aerobic exercise per week.
- If you read Stage 2 or Hypertensive Crisis, seek medical evaluation promptly — do not rely on lifestyle changes alone at this level.
Frequently Asked Questions
What do systolic and diastolic blood pressure numbers mean?
Systolic pressure (top number) measures the force in your arteries when your heart beats and pumps blood. Diastolic pressure (bottom number) measures the force when your heart rests between beats. A reading of 120/80 mmHg means systolic 120 and diastolic 80. Both numbers matter — high readings in either indicate hypertension.
What blood pressure is considered normal?
According to the 2017 American Heart Association guidelines, normal blood pressure is below 120/80 mmHg. Elevated is 120–129 systolic with less than 80 diastolic. Stage 1 hypertension begins at 130/80, Stage 2 at 140/90, and a hypertensive crisis is above 180/120 mmHg requiring immediate medical attention.
What causes high blood pressure?
Primary hypertension (essential hypertension) has no single cause and develops gradually. Key risk factors include a high-sodium diet, physical inactivity, obesity, excessive alcohol consumption, smoking, chronic stress, family history, and age. Secondary hypertension is caused by an underlying condition such as kidney disease or thyroid disorders.
How often should I check my blood pressure?
Adults with normal blood pressure should check it at least once every two years. Those with elevated blood pressure or hypertension should monitor more frequently — ideally daily or as directed by their doctor. For home monitoring, measure at the same time each day, sitting quietly for 5 minutes first, and take 2–3 readings 1 minute apart.
Can lifestyle changes lower blood pressure without medication?
Yes — lifestyle modifications can reduce systolic blood pressure by 4–11 mmHg each. Proven strategies include the DASH diet (rich in fruits, vegetables, whole grains), reducing sodium to under 2,300 mg/day, regular aerobic exercise (150 minutes/week), limiting alcohol, quitting smoking, maintaining a healthy weight, and managing stress through mindfulness or yoga.
This calculator is for educational purposes only. Consult a qualified healthcare professional for medical advice.