How to Calculate One Rep Max Calculator
What is One Rep Max Calculator?
One Rep Max (1RM) is the maximum weight you can lift for one complete repetition of an exercise. It is used to set training loads as percentages of 1RM. Direct 1RM testing is risky for beginners — submaximal prediction formulas estimate it from a set you can perform safely.
Step-by-Step Guide
- 1Lift a weight for as many reps as possible (ideally 3–10 reps)
- 2Apply prediction formula — Brzycki, Epley, or Lander
- 3Average the results for a more reliable estimate
- 4Set training weights as percentages of estimated 1RM
Worked Examples
Input
100 kg for 5 reps
Result
~116 kg 1RM
Brzycki: 100 × 36/(37-5) = 112.5 kg
Input
60 kg for 10 reps
Result
~80 kg 1RM
Epley: 60 × (1 + 10/30) = 80 kg