This calculator helps you determine your heart rate directly from an Electrocardiogram (ECG) strip. An ECG records the electrical activity of the heart, and by measuring the intervals between heartbeats on the strip, we can calculate the heart rate.
Method 1: Using the R-R Interval (Most Accurate for Regular Rhythms)
The R-R interval is the time between two consecutive R waves on the ECG. The R wave is the tallest peak in the QRS complex.
Method 2: Using the Number of Large Boxes (Good for Quick Estimates with Regular Rhythms)
Each large box on ECG graph paper represents 0.20 seconds. You can count the number of large boxes between two consecutive R waves.
Method 3: Using the 6-Second Strip Method (For Irregular Rhythms)
This method is useful when the heart rhythm is irregular. A standard ECG strip often records 10 seconds of tracing. To estimate from a 6-second strip, count the number of QRS complexes (the R wave is the most prominent part) within that 6-second window and multiply by 10.
function calculateHeartRate() {
var rrIntervalInput = document.getElementById("rrInterval");
var largeBoxesInput = document.getElementById("largeBoxes");
var qrsCountInput = document.getElementById("qrsCount");
var resultDiv = document.getElementById("result");
var rrInterval = parseFloat(rrIntervalInput.value);
var largeBoxes = parseFloat(largeBoxesInput.value);
var qrsCount = parseFloat(qrsCountInput.value);
var calculatedRate = null;
var message = "";
// Method 1: R-R Interval
if (!isNaN(rrInterval) && rrInterval > 0) {
calculatedRate = 60 / rrInterval;
message += "Method 1 (R-R Interval): Estimated Heart Rate = " + calculatedRate.toFixed(0) + " bpm";
}
// Method 2: Number of Large Boxes
if (!isNaN(largeBoxes) && largeBoxes > 0) {
var rrIntervalFromBoxes = largeBoxes * 0.20; // Each large box is 0.20 seconds
var rateFromBoxes = 60 / rrIntervalFromBoxes;
if (calculatedRate === null) { // Only show this if Method 1 wasn't used or valid
message += "Method 2 (Large Boxes): Estimated Heart Rate = " + rateFromBoxes.toFixed(0) + " bpm";
} else {
// You could add logic here to compare if both methods are used and the rhythm is likely regular
// For simplicity, we'll just append if Method 1 was also valid.
message += "Method 2 (Large Boxes): Estimated Heart Rate = " + rateFromBoxes.toFixed(0) + " bpm";
}
}
// Method 3: 6-Second Strip Method
if (!isNaN(qrsCount) && qrsCount > 0) {
var rateFrom6Sec = qrsCount * 10;
if (calculatedRate === null && (isNaN(largeBoxes) || largeBoxes <= 0)) { // Show this if other methods failed/weren't used
message += "Method 3 (6-Second Strip): Estimated Heart Rate = " + rateFrom6Sec.toFixed(0) + " bpm";
} else {
// Append for context if other methods were also used.
message += "Method 3 (6-Second Strip): Estimated Heart Rate = " + rateFrom6Sec.toFixed(0) + " bpm";
}
}
if (message === "") {
resultDiv.innerHTML = "Please enter valid numerical data for at least one method.";
} else {
resultDiv.innerHTML = "" + message + "";
}
}