function calculateBP() {
var sys = parseFloat(document.getElementById('systolic').value);
var dia = parseFloat(document.getElementById('diastolic').value);
var resultBox = document.getElementById('bp-result-box');
var categoryEl = document.getElementById('bp-category');
var descEl = document.getElementById('bp-description');
var mapEl = document.getElementById('map-value');
var ppEl = document.getElementById('pulse-pressure-value');
if (isNaN(sys) || isNaN(dia) || sys <= 0 || dia = 180 || dia >= 120) {
category = "Hypertensive Crisis";
description = "Emergency medical attention is required immediately.";
bgColor = "#800000";
borderColor = "#4d0000";
} else if (sys >= 140 || dia >= 90) {
category = "Hypertension Stage 2";
description = "High blood pressure that often requires medication and lifestyle changes.";
bgColor = "#e74c3c";
borderColor = "#c0392b";
} else if ((sys >= 130 && sys = 80 && dia = 120 && sys <= 129) && dia < 80) {
category = "Elevated";
description = "Blood pressure is elevated and likely to develop into hypertension unless steps are taken.";
bgColor = "#f1c40f";
textColor = "#333";
borderColor = "#f39c12";
} else if (sys < 120 && dia < 80) {
category = "Normal";
description = "Your blood pressure is within the healthy range.";
bgColor = "#2ecc71";
borderColor = "#27ae60";
} else {
// Edge case for mixed readings (e.g., 115/85)
category = "Hypertension Stage 1";
description = "One of your numbers indicates stage 1 hypertension.";
bgColor = "#f39c12";
borderColor = "#d35400";
}
// Calculations
var pulsePressure = sys – dia;
var map = (sys + (2 * dia)) / 3;
resultBox.style.display = 'block';
resultBox.style.backgroundColor = bgColor;
resultBox.style.color = textColor;
resultBox.style.borderLeftColor = borderColor;
categoryEl.innerText = category;
descEl.innerText = description;
mapEl.innerText = map.toFixed(1);
ppEl.innerText = pulsePressure.toFixed(0);
if (textColor === "#333") {
mapEl.style.color = "#333";
ppEl.style.color = "#333";
} else {
mapEl.style.color = "#fff";
ppEl.style.color = "#fff";
}
}
Understanding Blood Pressure Readings
Blood pressure is the force of your blood pushing against the walls of your arteries. Each time your heart beats, it pumps blood into the arteries. Your blood pressure is highest when your heart beats, pumping the blood. This is called systolic pressure. When your heart is at rest, between beats, your blood pressure falls. This is called diastolic pressure.
What do the numbers mean?
Blood pressure is measured in millimeters of mercury (mmHg) and is recorded with the systolic number over the diastolic number (e.g., 120/80 mmHg).
- Normal: Readings below 120/80 mmHg.
- Elevated: Systolic between 120-129 AND diastolic less than 80.
- Hypertension Stage 1: Systolic between 130-139 OR diastolic between 80-89.
- Hypertension Stage 2: Systolic 140 or higher OR diastolic 90 or higher.
- Hypertensive Crisis: Readings higher than 180/120 mmHg. Seek medical help immediately.
Mean Arterial Pressure (MAP) and Pulse Pressure
This calculator also provides two advanced metrics often used by clinicians:
Mean Arterial Pressure (MAP): This represents the average pressure in a person's arteries during one cardiac cycle. It is considered a better indicator of perfusion to vital organs than systolic blood pressure alone. A MAP between 70 and 100 mmHg is usually considered normal.
Pulse Pressure: This is the difference between your systolic and diastolic blood pressure (Systolic – Diastolic). It reflects the force that the heart generates each time it contracts. A consistently high pulse pressure (greater than 60 mmHg) can indicate stiffening of the arteries.
Real-Life Example Calculations
| Reading |
Category |
Pulse Pressure |
| 118/76 mmHg |
Normal |
42 mmHg |
| 135/85 mmHg |
Stage 1 Hypertension |
50 mmHg |
| 150/95 mmHg |
Stage 2 Hypertension |
55 mmHg |
Disclaimer: This calculator is for informational purposes only and does not constitute medical advice. A single high reading does not necessarily mean you have high blood pressure. Always consult with a healthcare professional for diagnosis and treatment.