This calculator is for informational purposes only and does not constitute medical advice. Results are estimates based on general formulas. Consult a qualified healthcare professional before making health decisions.
1 Rep Max
Estimate your maximum lifting strength and training zones.
Lift Details
Estimated One Rep Max
0 lbs
Training Percentages
| Intensity | Weight (lbs) | Est. Reps |
|---|
Your one-rep max (1RM) is the heaviest weight you could lift once with good form. Testing it directly is risky and fatiguing, so lifters estimate it from a set taken to (or near) failure at a lighter weight. The calculator applies the three most-cited estimation formulas and shows percentage-based training loads derived from the result.
Epley, Brzycki and Lombardi
Epley: 1RM = weight × (1 + reps ÷ 30). Brzycki: 1RM = weight × 36 ÷ (37 − reps). Lombardi: 1RM = weight × reps^0.10. All three agree closely up to about 5 reps and diverge as reps climb; Brzycki tends to estimate higher than Epley for sets of 8–10. None is reliable past 10–12 reps, because at that point muscular endurance, not maximal strength, limits the set. The calculator takes the average of the three as its headline figure.
When to use this calculator
Use it to set working weights for percentage-based programmes (5/3/1, linear progression, most powerlifting templates) without maxing out. Re-test every 4–8 weeks with a 3–5 rep set to keep the estimate current. Use the same lift, the same equipment and a fully rested state; a rep max taken at the end of a long session underestimates your true max. Beginners should treat the number as a guide, since technique changes quickly enough that estimates drift week to week.
Worked example
You squat 100 kg for 5 clean reps. Epley gives 100 × (1 + 5 ÷ 30) = 116.7 kg; Brzycki gives 100 × 36 ÷ 32 = 112.5 kg; Lombardi gives 100 × 5^0.10 ≈ 117.5 kg. The average is about 115.5 kg, so a programme calling for 3 sets of 5 at 80% would use roughly 92.5 kg, and a heavy triple at 90% about 104 kg.