One-rep max calculator
Your estimated max from any set, without testing it. Tap + and − to enter a set; hold a button to go faster.
Reps you had left
Counting the reps you had left makes the estimate much closer.
Estimated one-rep max
115.5 kg
| Reps | Weight | % of max |
|---|---|---|
| 1 | 115.5 kg | 100% |
| 2 | 110 kg | 95% |
| 3 | 106.5 kg | 92% |
| 4 | 103 kg | 89% |
| 5 | 100 kg | 87% |
| 6 | 97 kg | 84% |
| 7 | 94 kg | 81% |
| 8 | 91.5 kg | 79% |
| 9 | 88.5 kg | 77% |
| 10 | 86 kg | 74% |
| 11 | 84.5 kg | 73% |
| 12 | 82.5 kg | 71% |
How each formula sees it
The estimate above averages the formulas that fit 5 reps to failure (marked ✓).
- ✓ Epley (1985)116.5
- ✓ Brzycki (1993)112.5
- Lombardi (1989)117.5
- Mayhew (1992)119
- O'Conner (1989)112.5
- Wathan (1994)116.5
- Lander (1985)113.5
- ✓ Marzagao (2026)117.5
Questions
- How is the one-rep max estimated?
- From the weight and the reps you could have done to failure (your reps plus the reps you had left). Up to 10 reps to failure it averages Brzycki, Epley and a 2026 weight-dependent equation; above 10 it uses Mayhew, Wathan and the same newer equation, which hold up better at higher reps.
- Why count the reps I had left?
- The formulas assume you went to failure. A set of 5 with 2 reps left is really a 7-rep effort, so leaving that out makes the estimate low.
- How accurate is it?
- Closest from hard sets of 2 to 6 reps, still useful to about 10, and rough past 15. Treat it as a range, and watch the trend over time.
- Does Liftsmith track this for me?
- Yes. Every set you log updates the estimate for that lift, weighting recent and closer-to-failure sets more, and charts it over time.
More: how to estimate your one-rep max and reps in reserve.
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