Check your reading, get your classification, and track trends over time
Blood pressure is measured in mmHg and expressed as systolic (pressure during heartbeat) over diastolic (pressure between beats). Normal blood pressure is below 120/80 mmHg. High blood pressure (hypertension) significantly increases risk of heart disease, stroke, and kidney disease.
Readings can vary throughout the day. For the most accurate reading: sit quietly for 5 minutes, support your arm at heart level, and take 2–3 readings 1 minute apart. Use your average.
This tool is for informational purposes only. If you have high blood pressure or are concerned about your readings, consult a healthcare professional.
According to the American Heart Association (AHA), normal blood pressure is below 120/80 mmHg. Elevated is 120–129 systolic with diastolic below 80. Stage 1 hypertension is 130–139/80–89, and Stage 2 is 140+/90+. A reading of 180/120 or higher is a hypertensive crisis requiring immediate medical attention.
The top number (systolic) measures the pressure in your arteries when your heart beats and pumps blood. The bottom number (diastolic) measures the pressure when your heart rests between beats. Both numbers matter — high diastolic pressure is as important a risk factor as high systolic pressure.
Take readings at the same time each day for consistent tracking. Morning readings (before eating, taking medication, or exercising) and evening readings are both useful. Avoid measuring within 30 minutes of smoking, caffeine, or vigorous exercise. Sit quietly for 5 minutes before measuring, and support your arm at heart level.
Most high blood pressure (essential hypertension) has no single identified cause. Risk factors include age, family history, obesity, physical inactivity, high sodium diet, excessive alcohol, stress, and smoking. Secondary hypertension is caused by an underlying condition like kidney disease or thyroid disorders. Lifestyle changes and medication can effectively control blood pressure in most people.
Yes — blood pressure naturally rises and falls throughout the day. It's typically lowest during sleep and rises sharply upon waking. It can increase during physical activity, stress, or after eating. This is why single readings are less useful than tracking trends over time, which is exactly what this tracker is designed for.
Blood pressure is expressed as two numbers: systolic (the pressure when your heart beats and pumps blood) over diastolic (the pressure between beats when your heart rests). Both numbers matter independently. You can have normal systolic but elevated diastolic — or vice versa — and still be at increased cardiovascular risk.
The categories used in this tool follow the American Heart Association (AHA) 2017 guidelines, which lowered the hypertension threshold from 140/90 to 130/80. This change reflected research showing cardiovascular risk begins rising well below the old threshold. A single reading is rarely conclusive — blood pressure fluctuates throughout the day based on stress, caffeine, exercise, and even the act of being measured (white coat hypertension). Tracking multiple readings over time in consistent conditions gives a far more accurate picture.
Normal (below 120/80) — your cardiovascular risk from blood pressure alone is low. Continue healthy habits and check annually.
Elevated (120–129 / below 80) — not yet hypertension, but a signal. Lifestyle changes (less salt, more exercise, less alcohol) can bring this back to normal without medication.
High Stage 1 (130–139 / 80–89) — doctors typically recommend lifestyle changes and may consider medication if other cardiovascular risk factors are present.
High Stage 2 (140+ / 90+) — medication is usually recommended alongside lifestyle changes. Consult your doctor promptly.
Hypertensive Crisis (180+ / 120+) — seek medical attention immediately, especially with symptoms like chest pain, shortness of breath, or vision changes.
Low (below 90/60) — often harmless, but persistent low readings with dizziness or fainting warrant medical evaluation.
Blood pressure categories follow guidelines from the NHS and the American Heart Association.
Figures are estimates for guidance only. See about this site — how we source data and what these tools can and cannot do.
Blood pressure is expressed as two numbers: systolic (the higher number) represents the pressure in your arteries when your heart beats and pumps blood out. Diastolic (the lower number) represents the pressure between beats, when the heart is resting and refilling. Both numbers matter — isolated systolic hypertension (high systolic, normal diastolic) is particularly common in older adults and carries significant cardiovascular risk.
The categories used clinically: Normal is below 120/80 mmHg. Elevated is 120–129 systolic with less than 80 diastolic — a warning sign warranting lifestyle attention. Stage 1 hypertension is 130–139 systolic or 80–89 diastolic. Stage 2 hypertension is 140+ systolic or 90+ diastolic. A hypertensive crisis (requiring urgent care) is above 180/120 mmHg, particularly with symptoms like chest pain, severe headache, or visual disturbances.
Blood pressure is not constant — it fluctuates significantly throughout the day in response to activity, stress, caffeine, posture, temperature, and many other factors. It is typically lowest during sleep and rises sharply upon waking (the "morning surge"). A single reading in a clinic is often unrepresentative, particularly because the healthcare environment itself raises blood pressure in many people — a phenomenon called "white coat hypertension," affecting up to 20% of patients.
For accurate assessment, multiple readings taken over time are far more valuable than any single measurement. Measuring at the same time each day (morning before medications, or evening), in the same conditions (seated quietly for 5 minutes, arm supported at heart level), and averaging readings across several days gives a much better picture. This is why home blood pressure monitoring is increasingly recommended by cardiologists over relying solely on clinic measurements.
Salt (sodium): Excess dietary sodium causes the kidneys to retain water, increasing blood volume and therefore pressure. The NHS recommends no more than 6g of salt (2.4g sodium) per day for adults. Much of this comes from processed foods — bread, cereals, ready meals, sauces — rather than the salt you add at the table.
Alcohol: More than 14 units per week (UK guideline) consistently raises blood pressure over time. Drinking heavily also interferes with blood pressure medications. Even moderate regular drinking raises systolic pressure by 2–4 mmHg on average.
Weight: Each kilogram of excess weight raises blood pressure by approximately 1 mmHg. Weight loss is one of the most effective non-pharmacological interventions — a 5kg reduction can lower systolic pressure by 4–5 mmHg in overweight individuals.
Physical inactivity: Regular aerobic exercise (150 minutes/week of moderate intensity) lowers systolic blood pressure by 4–9 mmHg in hypertensive individuals. The effect appears within weeks of starting an exercise programme.
Blood pressure classification follows the 2017 American College of Cardiology/American Heart Association guidelines and the NICE guidelines for the UK (NG136). Salt recommendations are from NHS England. Exercise effects on blood pressure follow the Cochrane Review meta-analysis of aerobic exercise trials. This tool is for informational tracking purposes only — if you have elevated readings, consult your GP or healthcare provider.
Researched and maintained by Iulian, founder of Flux Media Systems. General information, not professional advice — about this site & our sources →