Blood Pressure Calculator
Check whether your reading is normal, elevated, or high.
About this tool
This calculator categorises your blood pressure using the 2017 ACC/AHA guideline, which is the most widely adopted clinical classification in the US, UK and Caribbean.
Blood pressure varies through the day — a single reading is rarely the full picture. Where possible, take two readings a few minutes apart, both morning and evening, for a week and average them.
Sources: 2017 ACC/AHA Hypertension Guideline; NICE NG136 (2019).
Frequently asked questions
Which reading matters more — top or bottom?
Both matter. After age 50 the top (systolic) reading is the stronger predictor of cardiovascular risk.
Is one high reading hypertension?
No. Diagnosis requires repeated raised readings on two or more separate occasions, ideally including home readings.
When should I worry?
A reading ≥180/120 with chest pain, weakness, vision changes or breathlessness is an emergency — call your local emergency services.
⚕️ Educational only — not a substitute for professional medical advice, diagnosis, or treatment. In an emergency call your local emergency services.