Strength calculator
1RM formula comparison calculator
Compare seven one-rep-max formulas from one set, then see their mean and spread.
MEAN e1RM
131 kg
FORMULA SPREAD
7.4%
Seven estimates
| Epley | w × (1 + r/30) | 133.3 kg |
|---|---|---|
| Brzycki | w × 36/(37 − r) | 133.3 kg |
| Lombardi | w × r^0.10 | 125.9 kg |
| Mayhew | 100w/(52.2 + 41.9e^−0.055r) | 130.9 kg |
| O'Conner | w × (1 + 0.025r) | 125 kg |
| Wathan | 100w/(48.8 + 53.8e^−0.075r) | 134.7 kg |
| Lander | 100w/(101.3 − 2.67123r) | 134.1 kg |
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What the comparison means
Epley and Brzycki rise quickly with repetitions; Lombardi, Mayhew, O'Conner, Wathan and Lander use different curves. The spread shows formula uncertainty, not measurement error. Estimates become less dependable as repetitions rise.