Work out heart rate from ecg instantly with clear inputs, formula shown and shareable results.
Turns the number of 1 mm ECG squares between consecutive R waves into a heart rate, using the recording paper speed.
Rate from R-R
R-R (s) = small squares / paper speed (mm/s); HR = 60 / R-R. At 25 mm/s this is the familiar 1500 / squares rule.
Educational estimate only. Not a substitute for professional clinical judgement, and must not be used to make treatment or dosing decisions.
At 25 mm/s each 1 mm square is 0.04 s, so 60 / (squares x 0.04) = 1500 / squares.
No. For an irregular rhythm count the QRS complexes over a 6-second strip and multiply by 10 instead.