:root {
–primary-color: #0056b3;
–secondary-color: #f0f7ff;
–accent-color: #e63946;
–text-color: #333;
–border-color: #ddd;
}
body {
font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
line-height: 1.6;
color: var(–text-color);
margin: 0;
padding: 20px;
}
.calculator-container {
max-width: 600px;
margin: 0 auto 40px auto;
background: #fff;
padding: 30px;
border-radius: 12px;
box-shadow: 0 4px 15px rgba(0,0,0,0.1);
border: 1px solid var(–border-color);
}
.calculator-title {
text-align: center;
color: var(–primary-color);
margin-bottom: 25px;
font-size: 24px;
font-weight: 700;
}
.input-group {
margin-bottom: 20px;
}
.input-group label {
display: block;
margin-bottom: 8px;
font-weight: 600;
color: #444;
}
.input-group select, .input-group input {
width: 100%;
padding: 12px;
border: 1px solid var(–border-color);
border-radius: 6px;
font-size: 16px;
box-sizing: border-box;
}
.input-group input:focus, .input-group select:focus {
outline: none;
border-color: var(–primary-color);
box-shadow: 0 0 0 2px rgba(0,86,179,0.1);
}
.helper-text {
font-size: 13px;
color: #666;
margin-top: 5px;
}
.calc-btn {
width: 100%;
background-color: var(–primary-color);
color: white;
border: none;
padding: 14px;
font-size: 18px;
font-weight: 600;
border-radius: 6px;
cursor: pointer;
transition: background-color 0.2s;
}
.calc-btn:hover {
background-color: #004494;
}
#result-area {
margin-top: 25px;
padding: 20px;
background-color: var(–secondary-color);
border-radius: 8px;
border-left: 5px solid var(–primary-color);
display: none;
}
.result-value {
font-size: 32px;
font-weight: bold;
color: var(–primary-color);
text-align: center;
display: block;
margin: 10px 0;
}
.result-label {
text-align: center;
font-size: 14px;
color: #555;
text-transform: uppercase;
letter-spacing: 1px;
}
.diagnosis {
text-align: center;
font-weight: 600;
margin-top: 10px;
padding: 5px 10px;
border-radius: 4px;
display: inline-block;
width: 100%;
box-sizing: border-box;
}
.status-normal { background-color: #d4edda; color: #155724; }
.status-brady { background-color: #fff3cd; color: #856404; }
.status-tachy { background-color: #f8d7da; color: #721c24; }
.article-content {
max-width: 800px;
margin: 0 auto;
background: #fff;
}
.article-content h2 {
color: #2c3e50;
margin-top: 30px;
border-bottom: 2px solid #eee;
padding-bottom: 10px;
}
.article-content h3 {
color: var(–primary-color);
margin-top: 25px;
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.article-content p, .article-content li {
font-size: 17px;
color: #444;
}
.article-content ul {
margin-left: 20px;
}
.highlight-box {
background: #f9f9f9;
border-left: 4px solid var(–primary-color);
padding: 15px;
margin: 20px 0;
}
How to Calculate Pulse Rate from ECG
Calculating the heart rate (pulse) from an Electrocardiogram (ECG/EKG) strip is a fundamental skill for medical professionals, students, and paramedics. The heart rate provides immediate insight into the patient's cardiac status, helping to identify tachycardia, bradycardia, or normal sinus rhythm.
Note: Standard ECG paper speed is 25 mm/second. The calculators and formulas below assume this standard setting.
Understanding the ECG Paper Grid
Before calculating, it is crucial to understand the dimensions of the ECG graph paper:
- Small Square: 1mm x 1mm. Represents 0.04 seconds in duration.
- Large Square: 5mm x 5mm. Made up of 5 small squares horizontally. Represents 0.20 seconds in duration.
Method 1: The 1500 Method (Most Precise)
The 1500 method is the most accurate way to calculate heart rate for regular rhythms. It uses the small squares on the grid.
Formula:
Heart Rate = 1500 / Number of Small Squares between R-R interval
Example: If there are 20 small squares between two consecutive R waves (peaks), the calculation is 1500 ÷ 20 = 75 BPM.
Method 2: The 300 Method (Quick Estimation)
This method is faster but slightly less precise. It is ideal for rapid assessment in emergency situations where the rhythm is regular.
Formula:
Heart Rate = 300 / Number of Large Squares between R-R interval
Sequence to Memorize: 300, 150, 100, 75, 60, 50. If the R-R interval is 1 large square, the rate is 300. If it is 2 squares, the rate is 150, and so on.
Example: If there are 4 large squares between R waves, the calculation is 300 ÷ 4 = 75 BPM.
Method 3: The 6-Second Strip Method (Irregular Rhythms)
If the patient has an irregular rhythm (such as Atrial Fibrillation), the R-R intervals vary, making the 1500 and 300 methods inaccurate. In this case, use the 6-second method.
Formula:
Heart Rate = Number of R Waves in a 6-second strip × 10
A 6-second strip consists of 30 large squares. Count the number of complexes (peaks) within these 30 large squares and multiply by 10 to get the average minute rate.
Interpreting the Results
Once you have calculated the BPM (Beats Per Minute), categorize the rate:
- Normal Sinus Rhythm: 60 to 100 BPM.
- Sinus Bradycardia: Less than 60 BPM (Slow heart rate).
- Sinus Tachycardia: Greater than 100 BPM (Fast heart rate).
function updateInputLabel() {
var method = document.getElementById('calcMethod').value;
var label = document.getElementById('dynamicLabel');
var helper = document.getElementById('methodHelper');
var input = document.getElementById('ecgValue');
// Reset input for safety
input.value = ";
if (method === '1500') {
label.innerText = 'Number of Small Squares between R waves';
helper.innerText = 'Most precise method. Count the small 1mm boxes between two R-wave peaks.';
} else if (method === '300') {
label.innerText = 'Number of Large Squares between R waves';
helper.innerText = 'Quick estimation. Count the heavy-line 5mm boxes between two R-wave peaks.';
} else if (method === '6sec') {
label.innerText = 'Number of R Waves (QRS complexes)';
helper.innerText = 'For irregular rhythms. Count total R-waves in a 6-second strip (30 large boxes).';
}
}
function calculateHeartRate() {
var method = document.getElementById('calcMethod').value;
var inputValue = parseFloat(document.getElementById('ecgValue').value);
var resultArea = document.getElementById('result-area');
var bpmDisplay = document.getElementById('bpmResult');
var diagnosisDisplay = document.getElementById('diagnosisResult');
var explanation = document.getElementById('calculationExplanation');
// Input validation
if (isNaN(inputValue) || inputValue <= 0) {
alert("Please enter a valid positive number.");
resultArea.style.display = 'none';
return;
}
var heartRate = 0;
var formulaText = "";
// Calculation Logic
if (method === '1500') {
heartRate = 1500 / inputValue;
formulaText = "1500 ÷ " + inputValue + " small squares = " + Math.round(heartRate) + " BPM";
} else if (method === '300') {
heartRate = 300 / inputValue;
formulaText = "300 ÷ " + inputValue + " large squares = " + Math.round(heartRate) + " BPM";
} else if (method === '6sec') {
heartRate = inputValue * 10;
formulaText = inputValue + " complexes × 10 = " + Math.round(heartRate) + " BPM";
}
// Round to nearest whole number
heartRate = Math.round(heartRate);
// Display Logic
bpmDisplay.innerText = heartRate + " BPM";
explanation.innerText = "Formula used: " + formulaText;
// Diagnosis Logic
diagnosisDisplay.className = 'diagnosis'; // reset classes
if (heartRate 100) {
diagnosisDisplay.innerText = "Tachycardia (Fast)";
diagnosisDisplay.classList.add('status-tachy');
} else {
diagnosisDisplay.innerText = "Normal Heart Rate";
diagnosisDisplay.classList.add('status-normal');
}
resultArea.style.display = 'block';
}