Calculate the Heart Rate in Ecg

ECG Heart Rate Calculator

Professional tool for medical diagnostics and rhythm analysis

Select Method: Choose based on rhythm regularity.

Most accurate for regular rhythms (1500 / squares)

Quick estimate for regular rhythms (300 / squares)

Count QRS complexes in a 30-large-square section (6 seconds)

Calculated Heart Rate:

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BPM

How to Calculate Heart Rate from an ECG

Electrocardiogram (ECG) paper standardly runs at a speed of 25 mm/sec. This means that time can be measured by the distance on the grid. To accurately calculate the heart rate, you must first identify the R-waves (the sharp peaks) and determine if the rhythm is regular or irregular.

1. The 1500 Method (Small Squares)

This is the most precise method for regular rhythms. Since there are 1,500 small squares in one minute (60 seconds / 0.04 seconds per small square), you divide 1,500 by the number of small squares between two consecutive R-waves.

• Formula: 1500 / (Number of Small Squares)
• Example: If there are 20 small squares between R-waves, 1500 / 20 = 75 BPM.

2. The 300 Method (Large Squares)

Used for a quick bedside estimation. There are 300 large squares in one minute. Divide 300 by the number of large squares between two R-waves.

• Formula: 300 / (Number of Large Squares)
• Sequence: 300, 150, 100, 75, 60, 50 (if R-waves fall exactly on large square lines).

3. The 6-Second Method

Essential for irregular rhythms like Atrial Fibrillation. Count the number of QRS complexes in a 6-second strip (30 large squares) and multiply by 10.

• Formula: (Number of QRS Complexes) x 10
• Example: 9 complexes in 6 seconds = 90 BPM.

Normal Heart Rate Ranges

Category	Heart Rate (BPM)
Bradycardia	Less than 60
Normal	60 – 100
Tachycardia	Greater than 100

function displayResult(bpm) { var resultBox = document.getElementById("ecgResultBox"); var hrValue = document.getElementById("hrValue"); var hrCategory = document.getElementById("hrCategory"); resultBox.style.display = "block"; hrValue.innerHTML = Math.round(bpm); if (bpm = 60 && bpm 0) { var bpm = 1500 / squares; displayResult(bpm); } else { alert("Please enter a valid number of small squares."); } } function calculateLarge() { var squares = parseFloat(document.getElementById("largeSquares").value); if (squares > 0) { var bpm = 300 / squares; displayResult(bpm); } else { alert("Please enter a valid number of large squares."); } } function calculateIrregular() { var complexes = parseFloat(document.getElementById("complexesCount").value); if (complexes > 0) { var bpm = complexes * 10; displayResult(bpm); } else { alert("Please enter the number of QRS complexes found in a 6-second strip."); } }