ECG Rate Calculator
This calculator helps you quickly determine the heart rate from an electrocardiogram (ECG/EKG) based on the R-R interval. Understanding your heart rate is crucial for assessing cardiac health.
Result:
Enter the R-R interval and other ECG parameters to calculate the heart rate.
Understanding ECG Heart Rate Calculation
The electrocardiogram (ECG or EKG) is a vital diagnostic tool that records the electrical activity of the heart. One of the most common measurements derived from an ECG is the heart rate. There are several methods to calculate heart rate from an ECG, depending on the regularity of the rhythm and the information available on the ECG strip.
Method 1: Using the R-R Interval (for regular rhythms)
When the heart rhythm is regular, you can calculate the heart rate by measuring the time between two consecutive R waves (the R-R interval). The standard formula is:
Heart Rate (beats per minute) = 60 / R-R Interval (in seconds)
For example, if the R-R interval is 0.8 seconds, the heart rate is 60 / 0.8 = 75 beats per minute.
Method 2: Using Small Boxes (for regular rhythms)
ECG paper is typically printed on a grid of small squares (1 mm x 1 mm) and larger squares formed by 5×5 small squares (5 mm x 5 mm). If the paper speed is 25 mm/sec, each small box represents 0.04 seconds (1 mm / 25 mm/sec), and each large box represents 0.20 seconds (5 mm / 25 mm/sec).
The formula is:
Heart Rate (beats per minute) = 1500 / Number of small boxes between two R waves
Alternatively, for faster calculation if the rhythm is reasonably regular:
Heart Rate (beats per minute) = 300 / Number of large boxes between two R waves
If there are approximately 4 large boxes between R waves, the heart rate is roughly 300 / 4 = 75 bpm.
Method 3: Using Heart Rate Strip Calculation (for irregular rhythms)
For irregular rhythms, the R-R interval method using a single interval can be misleading. It's best to measure the number of QRS complexes (heartbeats) over a longer period, typically 6 seconds, and multiply by 10.
Heart Rate (beats per minute) = Number of QRS complexes in 6 seconds x 10
How this Calculator Works
This calculator primarily uses the R-R interval in seconds for calculation, providing a direct and accurate heart rate. It also incorporates parameters like small box size, large box size, calibration, and paper speed, which are fundamental to interpreting ECG strips. While the main calculation is based on the R-R interval in seconds, understanding these other parameters is essential for comprehensive ECG analysis.
Important Note: This calculator is for informational purposes only and should not replace professional medical diagnosis. Always consult with a qualified healthcare provider for any health concerns.