One-Rep Max (1RM) Calculator

What is One-Rep Max (1RM) Calculator?

The One-Rep Max (1RM) Calculator determines your maximal single-repetition lifting capacity for bench press, squat, deadlift, or overhead press without performing a dangerous true maximal lift. Utilizing submaximal weight and repetition inputs (1–12 reps), it computes consensus 1RM across 7 validated sports science formulas with full percentage load breakdowns.

Designed for accuracy, speed, and privacy, this tool runs entirely on your local device with zero network latency.

How to Use the One-Rep Max (1RM) Calculator

1. 1
   Select your preferred weight unit (Pounds lbs or Kilograms kg).
2. 2
   Enter the submaximal weight you lifted during your set.
3. 3
   Enter the number of clean repetitions completed to failure (1 to 12 reps for highest accuracy).
4. 4
   Review your estimated 1RM consensus score and the detailed training percentage table (50% to 95% 1RM).

Formula & Calculation Logic

Computes nonlinear and linear submaximal rep-to-max mathematical models established by Epley (1985), Brzycki (1993), Lander (1985), Lombardi (1989), Mayhew et al. (1992), O'Conner et al. (1989), and Wathan (1994).