One Rep Max (1RM) Calculator

One Rep Max (1RM) is the maximum amount of weight you can lift for a single repetition with proper form. It is a fundamental measure of strength used by athletes, coaches, and fitness enthusiasts to program training and track progress.

Why Calculate Your 1RM?

• Program Design: Base training percentages on your actual strength
• Track Progress: Monitor strength gains over time
• Set Goals: Establish realistic strength targets
• Compare Performance: Benchmark across different exercises

Calculation Formulas:

• Epley: 1RM = Weight x (1 + Reps/30) - Most widely used, accurate for 1-10 reps
• Brzycki: 1RM = Weight x (36 / (37 - Reps)) - Linear relationship, best for 1-12 reps
• Lombardi: 1RM = Weight x Reps^0.10 - Good for higher rep ranges (10-15)

Training Zones:

• Strength (80-90% 1RM): 1-5 reps for maximum strength and power
• Hypertrophy (65-75% 1RM): 8-12 reps for muscle growth
• Endurance (50-65% 1RM): 15-20+ reps for muscular endurance

Tips for Accurate Estimation:

• Use weight you can lift with proper form for 3-10 reps
• Perform the set to near failure (1-2 reps in reserve)
• Rest adequately before the test set (2-3 minutes)
• Higher rep tests (10+) tend to overestimate 1RM

Important Considerations:

These calculations are estimates. Your actual 1RM may differ based on training experience, fatigue levels, technique proficiency, and exercise type. Always prioritize safety when testing maximal strength - use spotters and proper equipment.