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1RM Calculator | One Rep Max Calculator
Calculate your one-rep max (1RM) using Epley, Brzycki, and Lombardi formulas. Get percentage-based loading chart for any lift.
One Rep Max (1RM) Calculator
Estimate your one-rep max from any weight and rep count. See percentage-based loading for training.
How 1RM is Calculated
We use three validated formulas: Epley (1985): 1RM = w × (1 + r/30); Brzycki (1993): 1RM = w × 36/(37-r); Lombardi: 1RM = w × r^0.1. The result shown is the average of all three. These formulas are most accurate for 2-10 rep ranges. For higher reps (>12), accuracy decreases.
FAQ
What is 1RM?
One Rep Max (1RM) is the maximum weight you can lift for a single repetition with proper form. It is the standard measure of maximal strength in strength training and is used to calculate training loads.
How accurate is a 1RM calculator?
Calculated 1RM is typically within 5-10% of actual 1RM for rep ranges of 2-10. Accuracy decreases with higher rep counts. For the most accurate estimate, use sets of 3-5 reps.
What percentage of 1RM should I train at?
Strength: 85-100% for 1-5 reps. Hypertrophy: 65-80% for 6-12 reps. Endurance: 50-65% for 12-20+ reps. Most programs periodize across these ranges.
Which 1RM formula is the best?
The Epley and Brzycki formulas are most commonly used and validated. Brzycki tends to be slightly more accurate for lower reps (2-6), while Epley works better for moderate reps (5-10). We show the average of three formulas for the best estimate.
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