Estimate a one-rep max from a submaximal set using the Epley and Brzycki formulas.
| Epley 1RM | – |
| Brzycki 1RM | – |
Use this calculator to estimate a one-repetition maximum (1RM) from a set you actually completed. Enter the load and the repetitions. The load can be in kilograms (kg) or pounds (lb); the unit selector converts it automatically, and both 1RM results are shown in the same unit.
Epley: 1RM = weight × (1 + reps ÷ 30). Five reps at 100 kg is about 117 kg. Brzycki: 1RM = weight × 36 ÷ (37 − reps). The two estimates drift apart as reps climb. Both are gym rules of thumb, not a tested max. Keep reps in a strength range (about 1 to 12); the calculator rejects more than 12 reps because these formulas were not built for burnout sets.
Do not treat the result as a prescription for a heavy single. Warm-up, bar path, and spotters still matter.
Weight: Load on the bar. Enter kg or lb.
Reps: Repetitions completed, 1 to about 12.
Epley 1RM: Estimated max from the Epley formula.
Brzycki 1RM: Estimated max from the Brzycki formula.
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