Last updated: March 2026
How to Read a Blood Pressure Chart
A blood pressure chart maps your reading to one of five categories defined by the American Heart Association. Your blood pressure is expressed as two numbers — systolic over diastolic (for example, 120/80 mmHg). The systolic number measures arterial pressure when your heart contracts, and the diastolic number measures pressure when your heart rests between beats.
The interactive chart above goes beyond a static reference table. Enter your exact numbers to see your precise category with a visual gauge, color-coded badge, and personalized explanation. The tool also lets you log and track multiple readings over time, which is far more useful than checking a single snapshot.
Understanding Blood Pressure Categories
Normal blood pressure (below 120/80) means your heart and blood vessels are working efficiently. Maintaining this range through regular exercise, a balanced diet, and stress management is the goal for long-term cardiovascular health.
Elevated blood pressure (120-129/<80) is a warning sign. Without lifestyle changes, elevated readings often progress to full hypertension. At this stage, reducing sodium, increasing physical activity, and managing weight can make a meaningful difference.
Stage 1 and Stage 2 Hypertension indicate progressively higher cardiovascular risk. Stage 1 (130-139/80-89) may be managed with lifestyle changes alone, while Stage 2 (≥140/≥90) typically requires medication in addition to lifestyle modifications. Both stages benefit from regular monitoring and medical guidance.
Hypertensive Crisis (above 180/120) is a medical emergency. If you record this reading, wait five minutes and test again. If it remains elevated, seek immediate medical attention, especially if you experience chest pain, shortness of breath, vision changes, or difficulty speaking.
Health Disclaimer: This tool is for informational purposes only and does not constitute medical advice. Blood pressure classification is based on American Heart Association guidelines. For accurate diagnosis and treatment, consult your healthcare provider. A single reading does not diagnose hypertension.
Frequently Asked Questions
How do I read a blood pressure chart?
A blood pressure chart maps systolic (top number) and diastolic (bottom number) values to categories defined by the American Heart Association. Find your systolic reading on one axis and diastolic on the other — the intersection shows your category, from Normal (green) through Hypertensive Crisis (dark red).
What do the colors on the blood pressure chart mean?
Green represents Normal blood pressure (below 120/80), yellow is Elevated (120-129/<80), orange is Stage 1 Hypertension (130-139/80-89), red is Stage 2 Hypertension (140+/90+), and dark red is Hypertensive Crisis (above 180/120). The color coding provides a quick visual indicator of severity.
What blood pressure reading is considered dangerous?
A reading above 180/120 mmHg is classified as a Hypertensive Crisis and requires immediate medical attention. If you get this reading, wait 5 minutes and test again. If it remains above 180/120, contact your doctor or call 911, especially if you have symptoms like chest pain or vision changes.
Why do systolic and diastolic numbers matter differently?
Both numbers are important. Systolic pressure (top) indicates force when your heart beats, while diastolic (bottom) shows pressure between beats. When the two fall into different categories, the higher category applies to ensure elevated readings are not overlooked.
Is this blood pressure chart free to use?
Yes, completely free. No signup, no data stored on servers, no ads. Enter your numbers and instantly see your category. All calculations run in your browser, and the reading history is stored only in your current session.