One Rep Max Calculator
Estimate your 1RM from any weight and rep count. Uses three proven formulas and shows a full percentage breakdown.
How to Calculate Your One Rep Max
Your one rep max (1RM) is the maximum weight you can lift for a single repetition with proper form. This calculator uses three well-known formulas: Epley, Brzycki, and Lander. Each formula takes the weight you lifted and the number of reps you performed, then estimates what you could lift for one rep. The average of all three formulas gives the most reliable estimate.
The percentage chart shows how much weight to use at various intensities. For example, 85% of your 1RM is typically a 5-6 rep range, ideal for strength training. Use 70-75% for hypertrophy work (8-12 reps). These percentages apply to any barbell or dumbbell lift, including bench press, squat, deadlift, overhead press, and rows.