Blood Pressure Calculator

We use the categories most international guidelines follow. Below 120/80 is normal. 120–129 systolic with diastolic under 80 is elevated. Stage 1 hypertension is 130–139 over 80–89. Stage 2 is 140/90 or higher. A reading above 180/120 with symptoms is a hypertensive crisis — go to emergency. The higher of your two numbers decides the category, even if the other is normal. In my OPD we always take two readings five minutes apart, on both arms initially, before labelling anyone hypertensive. One reading is never the whole story.

MAP stands for Mean Arterial Pressure — the average pressure in your arteries during one heartbeat. The standard formula is MAP = diastolic + (systolic − diastolic) ÷ 3. So 120/80 gives a MAP of about 93 mmHg. Clinicians often aim for MAP above 65 mmHg in critical care patients to keep organs perfused, especially kidneys and brain. It matters more than systolic alone in shock or sepsis. For routine outpatient checks, clinicians still focus on the two numbers, but in ICU and during surgery, MAP is what care teams watch on the monitor.

No. This is one of the most important blood pressure interpretation rules. Blood pressure swings with stress, caffeine, recent exercise, white-coat anxiety in the clinic — sometimes 20 mmHg or more. Hypertension is diagnosed based on multiple readings on different days. Either three clinic visits at least a week apart, or 24-hour ambulatory monitoring, or two weeks of home readings twice daily. One isolated high reading should be a prompt to recheck, not to start medication. That said, a single reading above 180/120 with symptoms is treated immediately.

This pattern is called isolated systolic hypertension and it's common, especially after age 50. The arteries lose elasticity with age, so they don't expand and recoil with each heartbeat the way they used to. The systolic number rises while the diastolic stays normal or even drops a bit. It still increases your risk of stroke and heart attack, so it isn't 'safe' just because the bottom number looks fine. We treat it the same way — lifestyle changes first, medication if needed. The wider the gap, the stiffer the arteries usually are.

Pulse pressure is the difference between systolic and diastolic — the gap between your two numbers. A normal range is roughly 30 to 50 mmHg. So 120/80 gives a pulse pressure of 40, which is healthy. Above 60 suggests stiff arteries or aortic valve problems and predicts cardiovascular risk independently. Below 25 can mean low cardiac output or shock. In elderly patients we often see widened pulse pressures of 70 to 80 — a marker of arterial ageing. It's an underused number, but it tells us a lot about vascular health.

Any reading above 180/120 needs urgent attention, especially with symptoms like chest pain, severe headache, vision changes, breathlessness, weakness on one side, or confusion — that's a hypertensive emergency. Go straight to casualty. Without symptoms, the same numbers are called hypertensive urgency — still serious, but managed over hours rather than minutes. Pregnant women with readings above 140/90 should call their obstetrician the same day. And if your home machine gives a strange reading, recheck after 5 minutes of rest before panicking — equipment errors are common.