One-rep max calculator
Testing a true one-rep max is risky and tiring. A hard set of a few repetitions predicts it closely, and the three standard formulas are averaged to smooth out their disagreement. Training loads at common percentages follow.
- Epley
- 262.5 lb
- Brzycki
- 253.1 lb
- Lombardi
- 264.3 lb
- Gap between the formulas
- 11.2 lb
- Reliability of the estimate
- Good — five reps or fewer
| % of max | Load | Typical reps |
|---|---|---|
| 95 | 247 lb | 2 |
| 90 | 234 lb | 4 |
| 85 | 221 lb | 6 |
| 80 | 208 lb | 8 |
| 75 | 195 lb | 10 |
| 70 | 182 lb | 12 |
The formula
Epley: 1RM = w × (1 + r/30). Brzycki: 1RM = w × 36 / (37 − r). Lombardi: 1RM = w × r^0.10. The estimate shown is the mean of the three.
Worked example
100 kg for 5 repetitions gives 116.7 kg by Epley, 112.5 by Brzycki and 117.5 by Lombardi — an estimate of 115.5 kg. Working at 80% of that means sets around 92.4 kg.
How to use it
- 1Use a set taken to within one or two reps of failure with good form. An easy set underestimates.
- 2Keep the reps between 2 and 6 for the most reliable estimate. Beyond ten, all three formulas drift.
- 3Estimates differ by lift: they tend to be closer on the bench press and squat than on the deadlift.
Questions people ask
Should I test a real one-rep max instead?
Only with experience, a spotter and a proper warm-up. For most training purposes the estimate is accurate enough and carries far less injury risk.
Why does the reliability drop with more reps?
Endurance starts to matter as much as strength. Two people with the same maximum can manage very different numbers of reps at 70%, so the formulas lose their grip.
Last reviewed: 2026-10-20