ECG Heart Rate Calculator
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 primary pieces of information derived from an ECG is the heart rate, which indicates how many times the heart beats per minute (bpm).
The heart rate can be accurately calculated from an ECG by measuring the time between successive R waves (the highest peak in the QRS complex). This time interval is known as the R-R interval.
How it Works:
Using Seconds: If you measure the R-R interval in seconds (e.g., 0.8 seconds), the formula to calculate heart rate is:
Heart Rate (bpm) = 60 / R-R Interval (seconds)
For example, if the R-R interval is 0.8 seconds, the heart rate is 60 / 0.8 = 75 bpm.
Using Milliseconds: ECG paper often moves at a standard speed of 25 mm/second. Small boxes on ECG paper are typically 1 mm wide, representing 0.04 seconds (40 milliseconds). Larger boxes (5 small boxes) are 5 mm wide, representing 0.20 seconds (200 milliseconds). Measuring the R-R interval in milliseconds can sometimes be more precise. If you measure the R-R interval in milliseconds (e.g., 800 milliseconds), the formula is:
Heart Rate (bpm) = 60,000 / R-R Interval (milliseconds)
For example, if the R-R interval is 800 milliseconds, the heart rate is 60,000 / 800 = 75 bpm.
This calculator allows you to input either the R-R interval in seconds or milliseconds, and it will provide the calculated heart rate. If you input both, it will use the value that is not zero.