One-Rep Max Calculator
Calculate your one-repetition maximum (1RM) for strength training, powerlifting, and workout programming using proven formulas and training zones.
One-Rep Max Results
Calculation Details:
Training Zones (% of 1RM):
About
Our One-Rep Max Calculator helps athletes, powerlifters, and fitness enthusiasts estimate their maximum strength potential using scientifically validated formulas for safe and effective training program design.
Why Choose
Multiple proven formulas including Epley, Brzycki, and Lander, exercise-specific adjustments, training level considerations, and comprehensive training zone calculations for optimal workout programming.
Features
Seven different 1RM formulas, exercise type customization, training level adjustments, bodyweight ratio calculations, and detailed training zone breakdowns for strength, power, and hypertrophy.
Benefits
Design effective training programs, track strength progression, set realistic goals, optimize workout intensity, and reduce injury risk through proper load management and progressive overload.
Input Your Data
Enter the weight you lifted, number of repetitions performed, exercise type, and your training experience level for accurate 1RM estimation.
Choose Formula
Select from seven proven 1RM formulas or use the average for the most reliable estimate. Each formula has different strengths for various rep ranges.
Apply Results
Use your calculated 1RM and training zones to design effective workouts, track progress, and optimize your strength training program safely.
Frequently Asked Questions – One-Rep Max Calculator
1RM formulas are most accurate for 2-10 rep ranges, typically within 2-5% of actual 1RM. Accuracy decreases with very high reps (15+) or single rep tests. The Epley formula is most reliable for 1-6 reps, while Brzycki works better for 7-10 reps. Always approach calculated 1RM conservatively in actual training.
For 1-5 reps: Use Epley or Lombardi formulas. For 6-10 reps: Brzycki or Lander work best. For 10+ reps: Mayhew or O’Conner are more accurate. Powerlifters often prefer Epley, while bodybuilders may find Brzycki better for higher rep training. The “Average” option provides the most balanced estimate across all scenarios.
Strength (85-100%): 1-5 reps for max strength. Power (75-90%): 3-6 reps for explosive power. Hypertrophy (65-85%): 6-12 reps for muscle growth. Endurance (50-70%): 12-20 reps for muscular endurance. Warm-up (40-60%): Light sets to prepare muscles. Spend most training time in 65-85% range for optimal results.
Never attempt your calculated 1RM without proper preparation. Use the estimate for programming training loads at 85-95% instead. If testing actual 1RM, ensure proper warm-up, spotters, perfect form, and progressive buildup over weeks. Consider 3RM or 5RM tests as safer alternatives that still provide accurate estimates.
Recalculate every 4-6 weeks or when you can perform 2+ additional reps at the same weight. Beginners may see changes every 2-3 weeks, while advanced lifters might only see improvements every 8-12 weeks. Use the new 1RM to adjust training loads and ensure progressive overload continues effectively.