What's your one rep max?
7 formulas. Training zones. No guesswork.
Medical Disclaimer: This tool provides general educational estimates. Always consult your prescribing physician or healthcare provider before making medication changes or interpreting results from population-based models.
Frequently Asked Questions
Epley is recommended for 1-5 reps, Brzycki for 5-10 reps, and Mayhew for 10+ reps. This calculator averages all 7 formulas for the best overall estimate.
Most formulas are accurate within 5% for rep ranges of 2-10. Accuracy decreases significantly above 12 reps. For best results, use a weight you can lift 3-8 times.
Use percentages: 85-95% for strength (1-6 reps), 65-85% for hypertrophy (6-12 reps), 50-65% for endurance (15+ reps). Most programs use 1RM percentages to prescribe training loads.
Sources
- Epley B. Poundage Chart. Boyd Epley Workout. 1985.
- Brzycki M. Strength testing: predicting a one-rep max from reps-to-fatigue. JOPERD. 1993;64(1):88-90.
- NSCA. Essentials of Strength Training and Conditioning. 4th ed. Human Kinetics; 2016.
Methodology
Seven formulas are averaged: Epley (1985), Brzycki (1993), Lander (1985), Lombardi (1989), Mayhew et al. (1992), O'Conner et al. (1989), and Wathen (1994). Training zones follow NSCA guidelines: 85-100% for max strength, 67-85% for hypertrophy, 50-67% for muscular endurance.
One rep max (1RM) can be estimated from submaximal lifts using formulas. Epley: 1RM = weight × (1 + reps/30). Brzycki: 1RM = weight × 36/(37 - reps). Most accurate with 2-10 reps. Training zones: 85% for strength (6 reps), 75% for hypertrophy (10 reps), 65% for endurance (16 reps).
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