1 Rep Max

Calculate Your 1 Rep Max

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About 1 Rep Max (1RM)

The One Rep Max (1RM) is the maximum weight that can be lifted for a single repetition for a given exercise. It's a common measure of strength in weightlifting and strength training.

How it's calculated:

This calculator uses three popular formulas to estimate 1RM based on the weight lifted and the number of repetitions performed. See below for more details on each formula.

Uses of 1RM:

  • Measuring strength progress over time
  • Comparing strength levels between individuals
  • Determining appropriate weights for training programs

It's important to note that directly testing your 1RM can be risky, especially for beginners. These formulas provide a safer way to estimate your 1RM without the need to attempt a maximal lift.

1RM Calculation Formulas

Brzycki Formula

1RM = Weight / (1.0278 - 0.0278 × Reps)

  • Best for 1-10 reps
  • May underestimate 1RM for higher reps

Epley Formula

1RM = Weight × (1 + 0.0333 × Reps)

  • Generally accurate across a wide range of reps

Lander Formula

1RM = (100 × Weight) / (101.3 - 2.67123 × Reps)

  • Another widely used formula
  • Good for a range of rep counts