ECG Heart Rate

All health tools

Methods for calculating heart rate from an ECG rhythm strip.

EKG Measurements

Number of Small Squares (RR interval)

Most accurate for regular rhythm

Number of Large Squares (RR interval)

Quick estimate for regular rhythm

R-waves in 6-second strip (30 large squares)

Best for irregular rhythms (Afib)

Heart Rate (BPM)

1500 Method75BPM

300 Method75BPM

6-Second Method70BPMAvg Rate

Quick Reference (Regular)

1 Large = 300 BPM

2 Large = 150 BPM

3 Large = 100 BPM

4 Large = 75 BPM

5 Large = 60 BPM

6 Large = 50 BPM

Disclaimer: This tool is for informational purposes only. ECG interpretation requires professional clinical training and must consider the full medical context.

About this calculator

Overview

Calculating the heart rate is the first step in analyzing an EKG or ECG (Electrocardiogram). Depending on whether the heart rhythm is regular or irregular, various methods are used to determine the beats per minute (BPM) accurately.

💡

Pro Tips

Find an R-wave that lands on a heavy line to make counting large squares easier.
For irregular rhythms, always use the 6-second strip method to get an average heart rate.
Standard tachycardia is defined as > 100 BPM and bradycardia as < 60 BPM.

Fun Facts

"Normal paper speed is 25 mm/sec."
"One small square (1mm) = 0.04 seconds."
"One large square (5mm) = 0.20 seconds."
"The 1500 Method is the most accurate for regular rhythms."
"The 6-Second Method is necessary for irregular rhythms like Atrial Fibrillation."

Formula: 1500 Method: 1500 / Small Squares. 300 Method: 300 / Large Squares.