Compare bounded Epley, Brzycki, Lombardi and O’Conner lifting estimates, with observed one-rep handling and illustrative percentage loads.
01 / PURPOSE-SPECIFIC INPUTS
02 / RESULT & SUPPORTING WORK
One Rep Max (1RM) means the most weight you could lift once for a particular exercise. A calculated estimate is not proof of your lifting ability or a recommendation to attempt that weight.
Estimates do not guarantee lifting ability and are not instructions to attempt a maximum or unsafe load. Technique, fatigue, exercise selection and individual factors affect reliability. Use appropriate supervision and judgment; the percentage table is illustrative.
| Formula | Result (kg) |
|---|---|
| Epley | 116.67 |
| Brzycki | 112.5 |
| Lombardi | 117.46 |
| O'Conner | 112.5 |
| Percent | Unrounded target (kg) | Rounded loading (kg) | Estimated reps · unrounded target |
|---|---|---|---|
| 50% | 58.3333 | No increment selected | Not estimated · beyond 15-rep comparison range |
| 55% | 64.1667 | No increment selected | Not estimated · beyond 15-rep comparison range |
| 60% | 70 | No increment selected | Not estimated · beyond 15-rep comparison range |
| 65% | 75.8333 | No increment selected | Not estimated · beyond 15-rep comparison range |
| 70% | 81.6667 | No increment selected | About 11–13 reps |
| 75% | 87.5 | No increment selected | About 10 reps |
| 80% | 93.3333 | No increment selected | About 7–9 reps |
| 85% | 99.1667 | No increment selected | About 5–7 reps |
| 90% | 105 | No increment selected | About 3–5 reps |
| 95% | 110.8333 | No increment selected | About 1–3 reps |
| 100% | 116.6667 | No increment selected | About 1 rep |
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A completed submaximal set is compared across four bounded lifting equations. One actual completed rep remains an observation; the percentage table does not instruct a maximum attempt.
Compare Epley, Brzycki, Lombardi and O’Conner values, preserve observed one-rep loads and choose transparent loading-increment rounding.
One Rep Max Calculator inputs and calculations remain in browser memory. No external processing API receives entered measurements, formulas, dates or financial values. Ordinary website page requests may still be logged. Clipboard access occurs only when you choose Copy Result.
Epley uses W × (1 + reps/30); Brzycki uses W × 36/(37−reps); Lombardi uses W × reps^0.10; O’Conner uses W × (1 + reps/40). All use the same normalized lifted weight.
The actual lifted weight is used as the observed one-rep result for every comparison. The calculator does not extrapolate a higher value from a set already containing one repetition.
Only whole completed repetitions from one to fifteen. Reliability generally decreases at higher counts, especially above ten. Incomplete reps, different techniques and fatigue are not converted into guaranteed maximum ability.
Yes. The exact defined factor is 1 lb = 0.45359237 kg. Equations are evaluated on the same normalized weight, then results are displayed in the selected unit and supporting kilogram/pound forms.
Rows show arithmetic 50–100% fractions of the selected estimate. Optional total loading increments are explicitly rounded down or to nearest as selected; unrounded values remain visible. It is not a plate-loading optimizer or exercise prescription.
The calculator does not recommend attempting a maximum or unsafe load. Results are estimates rather than guaranteed lifting capability and depend on exercise, technique, experience and individual circumstances. Use appropriate judgment and supervision.