One Rep Max Calculator
Calculate your one-rep max using 7 different formulas with training percentage recommendations for optimal strength gains.
One Rep Max Calculator
Enter the weight you lifted and the number of reps you completed. Best results with 1-12 reps.
About One-Rep Max
Your one-rep max (1RM) is the maximum weight you can lift for a single repetition of a given exercise. It's a key metric in strength training, powerlifting, and athletic performance, used to measure progress and program training loads. This calculator uses seven validated formulas to estimate your 1RM.
•The Seven Formulas
- –Epley (1985): Most popular formula, simple and accurate for most lifters.
- –Brzycki (1993): Widely used in research, slightly conservative estimates.
- –Lander (1985): Good for higher rep ranges (8-12 reps).
- –Lombardi (1989): Power-based formula using logarithmic scaling.
- –Mayhew et al. (1992): Developed specifically for bench press.
- –O'Conner et al. (1989): Similar to Epley with slight variations.
- –Wathan (1994): Exponential formula, accurate across rep ranges.
•Training Percentage Guidelines
- –90-100%: Max strength (1-3 reps) - powerlifting, testing
- –80-90%: Strength building (3-6 reps) - primary strength work
- –70-80%: Hypertrophy focus (6-10 reps) - muscle building
- –60-70%: Strength endurance (10-15 reps) - conditioning
- –Below 60%: Muscular endurance (15+ reps) - warm-up, technique
•When to Test Your 1RM
- –Competition Day: Powerlifting meets or strength challenges.
- –Program Assessment: Every 8-12 weeks to measure progress.
- –Never When Injured: Always prioritize safety and proper form.
- –With a Spotter: Especially for bench press and squat variations.
•Tips for Accurate 1RM Testing
- –Proper Warm-Up: 10-15 minutes of dynamic movement and progressive loading.
- –Use Lower Reps: 1-5 rep estimates are most accurate; avoid testing beyond 10 reps.
- –Rest Adequately: 3-5 minutes between heavy attempts.
- –Perfect Form: Maintain strict technique; partial reps don't count.
- –Mental Preparation: Visualize success and stay focused.