Precision Utility
Blood Pressure
Calculator
Source
NHS/BHF
Method
Clinical Categories
Enter your systolic and diastolic blood pressure readings to see which NHS category you fall into. The calculator shows whether your numbers are low, normal, elevated or high — plus your pulse pressure. Based on NHS and British Heart Foundation guidelines.
Blood Pressure Reading
Your Reading
120/80
Normal
Systolic
120 mmHg
Diastolic
80 mmHg
Pulse Pressure
40 mmHg
Category
Normal
How the blood pressure calculator works
Enter your systolic reading (the top number) and your diastolic reading (the bottom number). These are the two values you get from a blood pressure monitor, measured in millimetres of mercury (mmHg).
The calculator compares both numbers against NHS and British Heart Foundation clinical thresholds to determine your category: low, normal, elevated, stage 1 hypertension, stage 2 hypertension, or hypertensive crisis.
Your result is based on whichever number falls into the higher category. For example, if your systolic is normal but your diastolic is elevated, the calculator will classify you as elevated — because the higher category takes priority.
You'll also see your pulse pressure, which is simply the difference between systolic and diastolic. A normal pulse pressure is around 40 mmHg. Values above 60 mmHg may suggest arterial stiffness and increased cardiovascular risk.
What you need to know about blood pressure
Blood pressure is the force of blood pushing against your artery walls as your heart pumps. It is one of the most important indicators of cardiovascular health and is checked routinely by the NHS.
NHS and BHF blood pressure categories:
- Low — below 90/60 mmHg. May cause dizziness or fainting in some people
- Normal — between 90/60 and 119/79 mmHg. The ideal range
- Elevated — 120–139/80–89 mmHg. Sometimes called pre-hypertension
- Stage 1 hypertension — 140–159/90–99 mmHg. Your GP may recommend lifestyle changes or medication
- Stage 2 hypertension — 160–179/100–119 mmHg. Medication is usually needed
- Hypertensive crisis — 180/120 mmHg or above. Seek urgent medical attention
What the numbers mean:
- Systolic (top number) — the pressure when your heart contracts and pushes blood out
- Diastolic (bottom number) — the pressure when your heart relaxes between beats
- Pulse pressure — the difference between systolic and diastolic. A wide gap (above 60 mmHg) can indicate stiff arteries
When to see your GP:
- Your home readings are consistently above 135/85 mmHg
- You experience headaches, blurred vision, chest pain or shortness of breath
- Your reading is above 180/120 mmHg — this is a hypertensive crisis and needs urgent attention
- You feel dizzy or faint regularly with low readings
This calculator is for general guidance only and does not replace professional medical advice. Always consult your GP or healthcare provider for a clinical assessment. Source: NHS, British Heart Foundation.
Frequently asked questions
What is a normal blood pressure reading?
A normal blood pressure reading is between 90/60 mmHg and 119/79 mmHg according to NHS guidelines. Readings consistently above 140/90 mmHg are classed as high blood pressure (hypertension).
What do the two numbers in a blood pressure reading mean?
The top number (systolic) measures the pressure in your arteries when your heart beats. The bottom number (diastolic) measures the pressure when your heart rests between beats. Both numbers matter when assessing your cardiovascular health.
What is pulse pressure and why does it matter?
Pulse pressure is the difference between your systolic and diastolic readings. A normal pulse pressure is around 40 mmHg. A wide pulse pressure (above 60 mmHg) may indicate stiff arteries and increased cardiovascular risk, especially in older adults.
How often should I check my blood pressure?
The NHS recommends healthy adults have their blood pressure checked at least every 5 years. If you have borderline or high readings, your GP may ask you to monitor more frequently — daily or weekly — using a home monitor.
Can blood pressure be too low?
Yes. Readings below 90/60 mmHg are considered low blood pressure (hypotension). While some people naturally have low blood pressure without symptoms, it can cause dizziness, fainting and fatigue. See your GP if low readings cause problems.
When should I see a GP about my blood pressure?
See your GP if your home readings are consistently above 135/85 mmHg, if you experience symptoms like headaches, blurred vision or chest pain, or if your reading is above 180/120 mmHg — which is a hypertensive crisis requiring urgent medical attention.