1RM Calculator — Estimate Your One Rep Max

Your one-rep max (1RM) is the heaviest weight you can lift for a single repetition with proper form. It is the gold standard for measuring absolute strength and the foundation of percentage-based training programs. Knowing your 1RM lets you program precise intensities for hypertrophy, strength, and peaking phases without guesswork.

Instead of risking injury with a true max attempt, this calculator uses proven regression formulas to estimate your 1RM from a submaximal set. Enter the weight you lifted and how many reps you completed, and the calculator will project your max using three well-established equations: Epley, Brzycki, and Lombardi.