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One-Rep Max (1RM) Calculator

Calculate Your 1RM

Quick Examples

Your 1RM Results

Enter your weight and reps to calculate your estimated 1RM

About One-Rep Max Calculator

The One-Rep Max (1RM) calculator estimates the maximum weight you can lift for one repetition based on your performance with submaximal weights. This is useful for programming training percentages and tracking strength progress.

Popular 1RM Formulas:

Brzycki Formula

Most popular: 1RM = weight × (36 / (37 - reps))

Epley Formula

1RM = weight × (1 + reps/30)

Lombardi Formula

1RM = weight × reps^0.1

O'Conner Formula

1RM = weight × (1 + reps/40)

Training Percentages:

90-100%: Maximal strength, neurological adaptation

80-89%: Strength development, low volume

70-79%: Muscle hypertrophy, moderate volume

60-69%: Muscular endurance, high volume