One Rep Max Calculator
Estimate your maximum lifting capacity (1RM) using 7 scientific formulas and check your strength standards.
Strength Standards (Optional)
Estimated 1RM (Average)
259.9 lbs
Estimated Repetitions Table
| Reps | Weight (lbs) | % 1RM | Training Zone |
|---|---|---|---|
| 1 | 259.9 | 100% | Peaking |
| 2 | 246.9 | 95% | Strength |
| 3 | 241.7 | 93% | Strength |
| 4 | 233.9 | 90% | Strength |
| 5 | 226.1 | 87% | Strength |
| 6 | 220.9 | 85% | Hypertrophy |
| 7 | 215.7 | 83% | Hypertrophy |
| 8 | 207.9 | 80% | Hypertrophy |
| 9 | 200.1 | 77% | Hypertrophy |
| 10 | 194.9 | 75% | Hypertrophy |
| 11 | 187.1 | 72% | Endurance |
| 12 | 181.9 | 70% | Endurance |
Formula breakdown
Epley262.5 lbs
Brzycki253.1 lbs
Lombardi264.3 lbs
Mayhew267.8 lbs
O'Conner253.1 lbs
Lander255.8 lbs
Wathan262.3 lbs
How one rep max is estimated
A one-repetition maximum (1RM) is the heaviest weight you can lift for exactly one repetition. Since testing true 1RM is risky, strength coaches use submaximal formulas: lift a weight you can handle for 2–10 reps, then estimate 1RM mathematically.
This tool averages seven formulas — Epley, Brzycki, Lombardi, Mayhew, O'Conner, Lander, and Wathan — for a balanced estimate. The training zones indicate which adaptation (strength, hypertrophy, or muscular endurance) is targeted by lifting that specific percentage of your 1RM.
Private & free — this tool runs entirely in your browser.
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