🏋️ One Rep Max Calculator
Estimate 1RM using the Epley formula
Estimate 1RM using the Epley formula
This calculator uses the Epley formula to estimate your 1RM (One Rep Max) — the maximum weight you can lift for one repetition. Enter the weight and maximum reps you can perform, and it will estimate your 1RM.
1RM is a core metric in strength training. Knowing your 1RM helps you scientifically plan training intensity, select appropriate working weights, and track strength progress.
Epley Formula: 1RM = Weight × (1 + Reps ÷ 30)
Training intensity relative to 1RM: - Strength: 85%-100% 1RM (1-5 reps) - Hypertrophy: 67%-85% 1RM (6-12 reps) - Endurance: 50%-67% 1RM (12+ reps)
Example: Bench press 80kg for 5 reps 1RM = 80 × (1 + 5/30) = 93.3kg
Safety tips: 1. Don't test true 1RM frequently — high injury risk 2. Formula estimation is sufficient, with ~5%-10% error 3. Always have a spotter for heavy lifts
This calculator is for reference only. Train according to your own ability and fitness level.