GetHealthyCalculators
Skip to content

Blood Pressure Calculator

Blood pressure is the force your blood exerts against the walls of your arteries. It is recorded as two numbers: systolic (the pressure when your heart beats) over diastolic (the pressure when your heart rests between beats). Knowing your numbers and what they mean is one of the most important steps you can take for cardiovascular health. This calculator classifies your reading using the landmark 2017 AHA/ACC Hypertension Guidelines.

Quick Answer

Normal blood pressure is below 120/80 mmHg. Readings of 130/80 or higher are classified as hypertension under the 2017 AHA/ACC guidelines.

These results are estimates based on general formulas and are not a substitute for professional medical advice. Consult a healthcare provider before making health decisions.

Enter your systolic and diastolic readings above to check your blood pressure category.

How the Formula Works

  1. Measure your systolic blood pressure — the top number — which reflects the pressure in your arteries when your heart contracts.

    Systolic = pressure during heartbeat (mmHg)

  2. Measure your diastolic blood pressure — the bottom number — which reflects the pressure in your arteries when your heart relaxes between beats.

    Diastolic = pressure between heartbeats (mmHg)

  3. Compare both values against the AHA/ACC 2017 classification thresholds. The higher of the two values determines your stage (for Stage 1 and Stage 2).

    Category = f(systolic, diastolic) per AHA/ACC 2017

Methodology & Sources

Reviewed and updated April 5, 2026 · Prepared by GetHealthyCalculators Editorial Team

This calculator applies the AHA/ACC 2017 Hypertension Guideline classification, which lowered the hypertension threshold from 140/90 to 130/80 mmHg. The OR logic for Stage 1 and Stage 2 means that exceeding either the systolic or diastolic threshold places a reading in that category.

References

How to Interpret Your Results

Blood pressure categories are defined by the 2017 American Heart Association (AHA) and American College of Cardiology (ACC) guideline update. Classifications are based on the higher of the two values, with specific AND/OR logic detailed in the guidelines. A single elevated reading does not establish a diagnosis — multiple measurements taken on separate occasions are required for clinical diagnosis.

Normal
0–119 — Systolic <120 AND diastolic <80 mmHg
Elevated
120–129 — Systolic 120–129 AND diastolic <80 mmHg
Stage 1 Hypertension
130–139 — Systolic 130–139 OR diastolic 80–89 mmHg
Stage 2 Hypertension
140–180 — Systolic ≥140 OR diastolic ≥90 mmHg
Hypertensive Crisis
181–999 — Systolic >180 OR diastolic >120 mmHg — seek emergency care

Limitations

  • A single blood pressure reading is not sufficient for a clinical diagnosis of hypertension. Multiple readings taken on at least two separate visits are required.
  • Blood pressure naturally varies throughout the day. Readings can be temporarily elevated by caffeine, exercise, stress, or "white coat hypertension" in clinical settings.
  • This tool uses AHA/ACC 2017 thresholds. Some international guidelines (e.g., ESC/ESH) use slightly different cutoffs.
  • Secondary hypertension (caused by an underlying condition) requires clinical evaluation and cannot be identified by blood pressure readings alone.
  • This calculator is a screening and educational tool only and does not constitute medical advice or diagnosis.

Frequently Asked Questions

What is a normal blood pressure reading?
According to the 2017 AHA/ACC guidelines, a normal blood pressure is less than 120/80 mmHg. Readings between 120–129 systolic with a diastolic below 80 are classified as elevated — a warning sign that hypertension may develop without lifestyle changes.
What do the two blood pressure numbers mean?
The top number (systolic) measures the pressure in your arteries when your heart beats. The bottom number (diastolic) measures the pressure between beats when your heart is resting. Both numbers matter and each can independently affect your cardiovascular risk category.
When is blood pressure considered dangerously high?
A hypertensive crisis occurs when systolic pressure exceeds 180 mmHg or diastolic exceeds 120 mmHg. This is a medical emergency that can cause organ damage, stroke, or heart attack and requires immediate emergency care.
How does the 2017 AHA/ACC guideline differ from older standards?
The 2017 guideline lowered the hypertension threshold from 140/90 mmHg to 130/80 mmHg. It also introduced the "Elevated" category (120–129/<80) and renamed the former "prehypertension" label. This change means more adults are now classified as having hypertension under current guidelines.
What lifestyle changes help lower blood pressure?
Evidence-based strategies include following the DASH diet (high in fruits, vegetables, and low-fat dairy), reducing sodium to under 2,300 mg per day, getting at least 150 minutes of moderate exercise per week, maintaining a healthy weight, limiting alcohol, and avoiding tobacco.
Can blood pressure vary throughout the day?
Yes. Blood pressure is lowest when you sleep and rises when you wake up. It can also increase temporarily due to exercise, stress, caffeine, and certain medications. For an accurate baseline, measure in the morning before eating or taking medications, and take two or three readings a minute apart.
Should I take blood pressure medication if my reading is in Stage 1?
For Stage 1 hypertension, the 2017 guidelines recommend lifestyle modifications as the first-line approach for most people. Medication is typically added if lifestyle changes are insufficient, if a second reading confirms Stage 1, or if the person has existing cardiovascular disease or a high 10-year risk. Always consult your doctor for personalized guidance.
Does high blood pressure cause symptoms?
High blood pressure is often called the "silent killer" because it typically causes no symptoms until it has caused significant damage. Severe or rapidly rising blood pressure can cause headaches, dizziness, or nosebleeds, but routine screening remains the only reliable way to detect it early.

Understand how your weight may be affecting your blood pressure

BMI Calculator

Related Calculators

Heart Disease Risk Calculator

Estimate your 10-year cardiovascular disease risk using the Framingham Risk Score.

Calculate

BMI Calculator

Calculate your Body Mass Index to assess your weight relative to your height.

Calculate