Count the number of large boxes between two consecutive R waves and use 300 ÷ number of large boxes
Count the number of small boxes between two consecutive R waves and use 1500 ÷ number of small boxes
Count the number of QRS complexes in a 6-second strip and multiply by 10
Use the sequence 300, 150, 100, 75, 60, 50 for regular rhythms by locating the R wave on the ECG grid
For irregular rhythms, count all QRS complexes over a measured time interval and convert to beats per minute
Measure the R-R interval and calculate heart rate using 60 ÷ R-R interval in seconds
Use the monitor’s displayed heart rate if the ECG machine is calibrated and functioning correctly