What is normal blood pressure in adults?
The American Heart Association classifies adult blood pressure as normal when systolic pressure is below 120 and diastolic pressure below 80 mmHg. One reading does not diagnose hypertension; diagnostic thresholds and treatment targets depend on the guideline and individual circumstances.
Details
Understanding the two numbers
The upper number measures pressure during a heartbeat; the lower number measures it between beats. Either can be raised independently. Clinic and home results sometimes differ, so a clinician may request a home record or ambulatory monitoring.
Measure before interpreting
Use a validated upper-arm monitor with a correctly sized cuff. Rest quietly and support your arm. Record measurements consistently rather than selecting the lowest value. UK guidance, for example, generally investigates clinic readings of 140/90 or above and confirms the diagnosis outside the clinic. This helps explain why thresholds differ between sources.
Symptoms matter too
Chest pain, severe breathlessness or trouble speaking requires emergency assessment regardless of the monitor reading. Do not increase or stop blood pressure medicine because of one measurement. Ask your clinician which threshold and treatment target apply to you.
Related reading: When and how often should I check blood pressure?.