How This Calculation Works
The one-rep max (1RM) calculator estimates the maximum weight you can lift for a single repetition, based on a submaximal lift. It uses three established formulas: Epley, Brzycki, and Lombardi.
The estimates are most accurate when you enter a weight you can lift for 2–10 reps. Beyond 10 reps, accuracy decreases significantly.
Common Mistakes to Avoid
- Using too many reps. Estimates become unreliable above 10 reps. Use a heavier weight for fewer reps for better accuracy.
- Testing 1RM without a spotter. Never attempt a true 1RM alone. Use the calculated estimate to guide your training.
- Ignoring form quality. Only count reps performed with proper form. Sloppy reps inflate the estimate.
Worked Example
Scenario: You bench press 80 kg for 6 reps.
Epley: 80 × (1 + 6/30) = 80 × 1.2 = 96 kg.
Brzycki: 80 × (36 / (37 − 6)) = 80 × 1.161 = 92.9 kg.
Average estimated 1RM: ~94–96 kg.