Blood pressure: what the numbers mean and when to act

Blood pressure is expressed as two numbers: systolic (top) over diastolic (bottom), measured in mmHg.

What the numbers mean

• Normal: below 120/80
• Elevated: 120-129 systolic, below 80 diastolic
• High (Stage 1): 130-139 / 80-89
• High (Stage 2): 140+ / 90+
• Hypertensive crisis: above 180/120 — seek urgent care

When to contact your GP

If readings are consistently above 140/90 over several days of home monitoring, make an appointment. If readings exceed 180/120 with symptoms (chest pain, difficulty breathing, severe headache), call 999.

Home monitoring tips

Take readings at the same time each day. Sit quietly for 5 minutes first. Take two readings and use the average. Log them in our free blood pressure log to share with your GP.