One Rep Max Calculator

Your one-rep max (1RM) is the maximum amount of weight you can lift for a single repetition of a given exercise. It is a fundamental measure of strength and serves as the basis for percentage-based training programs used by athletes and coaches worldwide. Our calculator estimates your 1RM without requiring you to actually attempt a maximal lift, which reduces injury risk.

Enter the weight you lifted and the number of reps you completed, and the calculator estimates your 1RM using multiple proven formulas including Epley, Brzycki, Lander, and Lombardi. It then generates a complete percentage chart showing recommended weights for training at various intensities - from light warm-up sets at 50% to heavy singles at 95%.

For the most accurate estimate, use a weight that you can lift for 2-8 reps with good form. Estimates become less reliable beyond 10 reps. The calculator works for any barbell or dumbbell exercise - bench press, squat, deadlift, overhead press, and more.