One Rep Max Calculator

About the One Rep Max Calculator

Your one rep max (1RM) is the maximum weight you can lift for a single repetition with proper form — the gold standard of absolute strength. While actually testing your 1RM is valuable, it is also fatiguing and carries injury risk. Our 1RM calculator estimates your max from a submaximal lift using the Epley, Brzycki, Lander, and Lombardi formulas, then provides your training percentages for any program.

How It Works

The Epley formula (most widely used): 1RM = weight × (1 + reps/30). The Brzycki formula: 1RM = weight / (1.0278 − 0.0278 × reps). Both formulas are most accurate for sets of 2-10 reps. For reps above 10, accuracy declines significantly. For example, a 185 lb bench press for 5 reps gives an estimated 1RM of 208 lbs (Epley) or 209 lbs (Brzycki). These values are used to calculate training percentages: 70% for hypertrophy, 85-95% for strength, 95-100%+ for power.

Tips & Best Practices

• ✓Powerlifting training percentages: 85-90% for 3-5 rep strength work, 70-75% for 8-12 rep hypertrophy.
• ✓Accuracy is best with 2-6 rep sets — 10+ rep estimates have higher error.
• ✓1RM standards for men bench press: Beginner <0.5× BW, Intermediate 1× BW, Advanced 1.5× BW, Elite 2× BW.
• ✓Track estimated 1RM over time to monitor strength progress without max-effort testing every cycle.
• ✓Different exercises have different strength ratios: most lifters squat 20-30% more than they bench.

Who Uses This Calculator

Powerlifters and weightlifters programming percentage-based training, personal trainers setting client load prescriptions, strength coaches monitoring team athlete development, and recreational gym-goers tracking long-term progress all use 1RM estimates regularly.