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One Rep Max Calculator

Calculate your maximum weight for one repetition using multiple proven formulas.

kg
reps
92.4 kg

Individual Formula Results

Epley: 93.3 kg
Brzycki: 90.0 kg
Lander: 91.0 kg
Lombardi: 94.0 kg
Mayhew: 95.2 kg
O'Conner: 90.0 kg
Wathan: 93.3 kg

Training Percentages

50% of 1RM
46.2 kg
60% of 1RM
55.4 kg
70% of 1RM
64.7 kg
75% of 1RM
69.3 kg
80% of 1RM
73.9 kg
85% of 1RM
78.5 kg
90% of 1RM
83.2 kg
95% of 1RM
87.8 kg
What is One Rep Max (1RM)?

One Rep Max (1RM) is the maximum amount of weight you can lift for a single repetition of a given exercise. It's a key metric in strength training used to:

  • Determine training loads and percentages
  • Track strength progress over time
  • Compare performance across different exercises
  • Design periodized training programs
1RM Calculation Formulas

This calculator uses 7 proven formulas to estimate your 1RM:

  • Epley: 1RM = Weight × (1 + Reps/30)
  • Brzycki: 1RM = Weight × (36/(37-Reps))
  • Lander: Most accurate for 2-10 reps
  • Lombardi: Uses exponential calculation
  • Mayhew: Based on exponential regression
  • O'Conner: Simple linear formula
  • Wathan: Alternative exponential method

The average of all formulas provides the most reliable estimate.

Training Percentages Guide

Common training percentages and their typical uses:

  • 50-60%: Warm-up, technique work, high-volume training
  • 70-75%: Hypertrophy (muscle building), moderate intensity
  • 80-85%: Strength training, lower rep ranges
  • 90-95%: Maximum strength, powerlifting, peaking

Safety Note: Always warm up properly and consider having a spotter when lifting heavy weights.