Blood pressure readings have two numbers. The first number provides your systolic pressure, and the second number provides your dystolic pressure. In adults and children of 13 years or older, blood pressure measurements fall into the following four categories: (1) Normal blood pressure: below 120/80 mmHg, (2) Elevated blood pressure: systolic pressure ranging from 120-129 mmHg and diastolic pressure below 80 mmHg. Elevated blood pressure is likely to get worse overtime unless steps are taken to control blood pressure. (3) Stage 1 hypertension: systolic pressure ranging from 130-139 mmHg or a diastolic pressure ranging from 80-89 mmHg. (4) Stage 2 hypertension: systolic pressure of at least 140 mmHg or diastolic pressure of at least 90 mmHg. If there is a discrepancy in category between the systolic and diastolic pressures, the higher value determines the stage.
Reference:
Mayo Clinic: https://www.mayoclinic.org/diseases-conditions/high-blood-pressure/diagnosis-treatment/drc-20373417