basic

Brzycki One-Rep Max (1RM) Calculator

1RM = w / (1.0278 − 0.0278 · r) — best for r ≤ 10.

Estimate the one-rep max for any compound lift from a sub-maximal weight × reps set using Matt Brzycki's classic formula: 1RM = w / (1.0278 − 0.0278 · r), accurate up to about 10 reps. Above 10 reps, accuracy drops as the rep range becomes more endurance-driven.

Marcus Laurent By Marcus Laurent
Published Last reviewed 1 min read

Inputs

lb

Results

Enter values and click Calculate to see results.
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How to use this calculator

  1. Fill in the inputs above using the units you already have.
  2. Values update automatically as you type — no submit button needed.
  3. Hover any result row for the underlying formula and intermediate values.

Formula

1RM = w / (1.0278 − 0.0278 · r).

In depth

Estimate the one-rep max for any compound lift from a sub-maximal weight × reps set using Matt Brzycki's classic formula: 1RM = w / (1.0278 − 0.0278 · r), accurate up to about 10 reps. Above 10 reps, accuracy drops as the rep range becomes more endurance-driven.