Benchmark, 48 figures
2026 one-rep-max formula disagreement benchmark
Six published 1RM formulas estimate the same max from the same set, then disagree. This benchmark holds the lifted weight at 110 kg and sweeps reps to show how far the estimates fan out. At 5 reps the six formulas span 7.2 kg (5.6% of the average); at 12 reps the spread widens to 17.8 kg (11.7%). The formulas agree most closely at 8 reps (3.6%). The spread shows how much the formulas disagree, not how far any one is from a tested max; when 5-, 10- and 20-rep sets were tested against measured maxes, the 5-rep set predicted best (Reynolds et al., 2006).
Every value below is computed live from the one-rep-max calculator engine. Read the methodology for each formula's equation, or the article on which 1RM formula to trust. The spread is a property of the formulas, not a measured human error.
1RM estimate by reps (rows) and formula (columns)
Estimated 1RM (kg) from 110 kg. Rows: reps performed. Columns: formula.
| reps \ formula | Epley | Brzycki | Lombardi | Mayhew | Wathen | Lander | Spread |
|---|---|---|---|---|---|---|---|
| 2 | 117.3 | 113.1 | 117.9 | 122.6 | 115.7 | 114.6 | 9.4 kg |
| 3 | 121.0 | 116.5 | 122.8 | 125.4 | 119.9 | 117.9 | 8.9 kg |
| 4 | 124.7 | 120.0 | 126.4 | 128.2 | 124.1 | 121.4 | 8.2 kg |
| 5 | 128.3 | 123.8 | 129.2 | 130.9 | 128.2 | 125.1 | 7.2 kg |
| 6 | 132.0 | 127.7 | 131.6 | 133.6 | 132.4 | 129.0 | 5.9 kg |
| 8 | 139.3 | 136.6 | 135.4 | 138.9 | 140.4 | 137.6 | 5.0 kg |
| 10 | 146.7 | 146.7 | 138.5 | 144.0 | 148.2 | 147.5 | 9.7 kg |
| 12 | 154.0 | 158.4 | 141.0 | 148.9 | 155.6 | 158.9 | 17.8 kg |
Cells are each formula's estimated one-rep max from a 110 kg lift at the row's rep count. The Spread column is the range between the highest and lowest estimate on that row. The estimates agree most closely at 8 reps and diverge quickly above 10, where each formula's curve shape (linear, reciprocal, power-law or exponential) dominates.
How the table is made
- Engine
- One-Rep-Max Calculator (one-rep-max-calculator)
- Source
- Computed live from /engines/one-rep-max-calculator.js
- Rows
- Reps: 2, 3, 4, 5, 6, 8, 10, 12
- Columns
- Formula: Epley, Brzycki, Lombardi, Mayhew, Wathen, Lander
- Fixed input
- weight lifted = 110 kg
- Size
- 8 reps × 6 formulas = 48 cells
- Each figure
- Estimated 1RM (kg) and inter-formula spread
- Grid last changed
- , recomputed on every build
Generation note: the engine is deterministic, with no wall-clock and no randomness, so each cell reproduces exactly on every build. The full grid is embedded as machine-readable JSON and recomputed by our CI gate against a fresh engine run; the table, spread, and CSV are rendered from those same outputs, never hand-entered. This benchmark compares formula outputs, not independent measurements against a gold standard.