One-Rep Max Calculator (Brzycki / Epley / Lombardi)
1RM from a sub-max set using Brzycki, Epley, and Lombardi formulas — three estimates side by side.
Result
Estimated 1RM (avg)
260.0 lb
Brzycki 253.1 · Epley 262.5 · Lombardi 264.3.
- Lifted225 lb × 5 reps
- Brzycki 1RM253.1 lb
- Epley 1RM262.5 lb
- Lombardi 1RM264.3 lb
- Average260.0 lb
Step-by-step
- Brzycki: w × 36 / (37 − reps) = 225 × 36 / 32 = 253.1.
- Epley: w × (1 + reps / 30) = 225 × 1.1667 = 262.5.
- Lombardi: w × reps^0.10 = 225 × 1.1746 = 264.3.
How to use this calculator
- Pick a weight you can do for 3-8 reps with good form.
- Enter weight + unit + actual reps.
- Use the average for programming sets at % of 1RM.
About this calculator
1RM (one-rep maximum) is the heaviest weight you can lift once for a given exercise. Three classic prediction formulas: Brzycki tends low at high reps, Epley tends high, Lombardi is the most stable across rep ranges. All three converge below 5 reps; above 8-10 reps they diverge by 5-15%. Use the average for programming. Don't test true 1RM more than every 4-8 weeks — it's neurally taxing and injury-prone for non-elite lifters. Most coaches program off estimated 1RM, not tested.
Frequently asked
For 3-5 reps: all three converge. For 6-10: average them. Above 10 reps: estimates are unreliable — drop weight and retest at 5-8 reps.
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