Blood pressure chart and calculator

U.S. doctors use the 2017 American College of Cardiology / American Heart Association guideline:

When the two numbers fall into different categories, the higher category applies. For example, 128/84 is stage 1 because of the bottom number.

Blood pressure changes from minute to minute. One reading can be high because you just climbed stairs, had coffee or felt nervous at the doctor's office ("white coat" effect). That's why guidelines base decisions on the average of several readings taken on different days.

The calculator averages all valid readings you enter. With three or more readings you can tick "Skip the first reading", because the first measurement is often a little higher. If your readings differ by more than 10 mmHg, it suggests resting and measuring again.

• Avoid caffeine, exercise and smoking for 30 minutes before measuring.
• Sit quietly for 5 minutes with your back supported and feet flat on the floor, legs uncrossed.
• Rest your arm on a table so the cuff is at heart level, on bare skin.
• Use a validated upper-arm cuff in the right size.
• Take two readings one to two minutes apart, morning and evening, for at least 3 and ideally 7 days, and average them.

The calculator also shows the European ESC 2024 classification and, in the chart below the results, the ESH 2023 grades. The European guidelines draw lines in slightly different places: ESC calls readings under 120/70 "non-elevated" and treats 140/90 at the office (135/85 at home) as hypertension, while the U.S. guideline already calls 130/80 stage 1 hypertension. The categories are a starting point for a conversation with your doctor, who decides on diagnosis and treatment.

If a reading is higher than 180/120 mmHg and you have symptoms such as chest pain, shortness of breath, back pain, numbness or weakness, a change in vision or difficulty speaking, call 911. Without symptoms, rest for five minutes and measure again; if it's still that high, contact your doctor right away.

High blood pressure usually causes no symptoms at all, which is why regular checks matter. If your average is elevated or in a hypertension stage, keep a log and share it with your doctor. This calculator is informational and isn't medical advice or a diagnosis. Your readings stay in your browser.