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One-Rep Max Calculator

You do not need to test a true max to train with percentages. Take any recent hard set, enter the weight and reps, and get an estimated one-rep max from two published formulas, plus a loading table for your next block.
Unit

A recent set taken close to failure with good form.

Most accurate under 10 reps.

Estimated one-rep max

Enter a recent hard set (weight and reps) and choose Estimate my 1RM.

Sources

  1. Poundage chart. Boyd Epley workout Epley B, University of Nebraska, 19851RM = weight x (1 + reps / 30).
  2. Strength testing: predicting a one-rep max from reps-to-fatigue Brzycki M, Journal of Physical Education, Recreation and Dance, 19931RM = weight x 36 / (37 - reps). Both formulas are most accurate below 10 reps.

Last reviewed: 2026-07-16