One Rep Max (1RM) Calculator

Estimate your maximum strength with CalcZen

Weight Lifted

Reps Performed

*Formulas are most accurate under 12 reps.

Estimated 1RM

lbs/kg

Percentage	Weight

Epley: -

Brzycki: -

CalcZen uses the average of Epley and Brzycki for the most reliable estimate across different rep ranges.