🏋️ One Rep Max Calculator
Estimate your one rep max from weight and reps
How 1RM Estimation Works
Formula
1RM (Epley) = Weight × (1 + Reps / 30)
- 1Enter the weight you lifted.
- 2Enter the number of reps you completed (up to about 10 for best accuracy).
- 3The calculator applies multiple 1RM formulas (Epley, Brzycki, Lombardi).
- 4Results show your estimated 1RM and training percentages.
- 5A loading chart shows weights for common training percentages (50-95%).
About One Rep Max Calculator
Calculate your one rep max (1RM) from weight and reps performed. Uses Epley, Brzycki, and Lombardi formulas. Plan training percentages for strength and hypertrophy programs.
Frequently Asked Questions
How accurate are 1RM calculators?
Most accurate with 1-5 reps. Accuracy decreases above 10 reps. Different formulas may vary by 5-10%. Use it as a training guide, not an exact measurement. For a true 1RM, test under proper supervision.
What percentage of 1RM should I train at?
Strength: 80-95% for 1-5 reps. Hypertrophy (muscle growth): 65-80% for 6-12 reps. Endurance: 50-65% for 15+ reps. Periodize your training across these ranges for best results.
Which 1RM formula is best?
Brzycki and Epley are the most commonly used. Brzycki tends to be more conservative. Most formulas agree closely for low rep ranges (1-6). Use the average of multiple formulas for the best estimate.