One-Rep Max Formulas
Epley: 1RM = Weight × (1 + Reps/30). Brzycki: 1RM = Weight × 36/(37-Reps).
Training by Percentage
| Goal | %1RM | Reps |
|---|---|---|
| Strength | 85-100% | 1-5 |
| Hypertrophy | 67-85% | 6-12 |
| Endurance | 50-67% | 12-20 |
How to Use This One-Rep Max Calculator
Enter the weight lifted and the number of reps completed (up to 10 reps for accuracy). The calculator estimates your one-rep max using multiple formulas.
Formula & How It Works
Epley: 1RM = Weight Γ (1 + Reps/30). Brzycki: 1RM = Weight Γ 36 / (37 β Reps). Lander: 1RM = Weight Γ 100 / (101.3 β 2.67 Γ Reps).
Calculation Example
Bench press 185 lbs Γ 6 reps: Epley 1RM = 185 Γ (1 + 6/30) = 222 lbs. Percentage chart: 80% (178 lbs) for 8 reps, 70% (155 lbs) for 12 reps.
Expert Tips
Use sub-maximal testing (3-5 reps) for the most accurate estimate β formulas lose accuracy above 10 reps. Warm up thoroughly before heavy attempts. Test 1RM only when well-rested and recovered.
Frequently Asked Questions
How accurate is the 1RM estimate?
Most accurate with 1-5 reps. Above 10 reps, accuracy decreases. Best to test periodically with an actual 1RM.
Should beginners test 1RM?
Beginners should use estimated 1RM. Test actual 1RM only after developing proper form and building a strength base.
Which formula is better?
Epley and Brzycki are both reliable for low rep ranges. Brzycki tends to be more accurate under 10 reps.