Home/Health & Fitness Calculators/ECG Heart Rate Calculator Health & Fitness Calculators ECG Heart Rate Calculator EditorLast Updated: April 6, 2024 RR Interval mm OR cm no. of boxes RR Interval Distance cm mm Interval Boxes Small (1 mm) Big (5 mm) Paper Speed 25 mm/s 50 mm/s Calculate Reset EditorLast Updated: April 6, 2024 Facebook X LinkedIn Pinterest Share via Email Print