One Rep Max (1RM) Calculator

Free 1RM calculator using the Epley formula. Estimate the maximum weight you can lift for one repetition and get training percentages for strength, hypertrophy, and endurance.

How It Works

Enter the weight you lifted and the number of reps you completed. The calculator uses the Epley formula (1RM = Weight × (1 + Reps / 30)) to estimate your one rep max and provides percentage-based training zones.