One Rep Max (1RM) Calculator

Estimate and calculate your true One Rep Max (1RM)—the gold standard benchmark of maximal muscular strength and neural recruitment in resistance training, powerlifting, bodybuilding, and Olympic weightlifting. Instead of risking injury with dangerous unassisted true maximum attempts, this scientific strength calculator accurately projects your 1RM from submaximal sets (1 to 12 reps) using seven peer-reviewed exercise physiology equations: Brzycki, Epley, Lombardi, O’Conner et al., Mayhew et al., Wathan, and Lander.

Features include multi-formula consensus averages, comprehensive repetition max tables (1RM through 12RM), barbell plate loading breakdown calculator (45 lb / 20 kg standard Olympic collars), and training percentage intensity brackets (from 50% recovery up to 95% near-max strength) with optimal rep ranges for hypertrophy, strength, and explosive power.