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Rep max

Repetition maximum Also called RM, 5RM, 10RM, repetition maximum, 5 rep max

A rep max is the heaviest weight you can lift for a given number of reps and no more: a 5RM is the most you can lift five times.

75 kg × 1075%85 kg × 585%90 kg × 390%100 kg × 1100%
100 kg for 1: 100% of 100 kg. With a 100 kg one-rep max, the Epley formula puts your 3RM near 90 kg, your 5RM near 85 kg and your 10RM at 75 kg.

In plain words

Pick a rep number. The heaviest weight you can manage for that many is your rep max. Lifters write it with RM after the number: a 5RM is your five-rep best, a 10RM your ten-rep best, and a one-rep max is the 1RM. Research and older programs set loads this way; the ACSM's 2009 position stand speaks of an 8–12 repetition maximum for novices and 1–6 RM for heavy work. A rep max belongs to one lift, and the step from one rep max to another is an estimate: a 2024 meta-regression of 952 tests found the reps people manage at a given percentage differ by lift, with more on the leg press than the bench press.

An example

Say your one-rep max is 100 kg. By the Epley formula, the weight for three reps is 90.9 kg, for five reps 85.7 kg, and for ten reps 75.0 kg. Rounded to the plates you have, that is a 3RM near 90 kg, a 5RM near 85 kg and a 10RM of 75 kg. Four rep maxes, same lifter, same day.

Often confused with

One-rep max The one-rep max is the 1RM, the top of the ladder; a rep max can be for any number of reps. Rep range A rep range like 8–12 is a target to work between; an 8RM is a tested limit.
One-rep max A one-rep max, or 1RM, is the heaviest weight you can lift for one full rep of an exercise, and no more.
Estimated 1RM An estimated 1RM, or e1RM, is a calculated guess at your one-rep max, worked out from a set of several reps with a formula instead of a heavy single.
Epley formula The Epley formula estimates a one-rep max from a set of several reps: one-rep max = weight × (1 + reps ÷ 30).
Percentage of 1RM A percentage of 1RM is a way to set a weight as a share of your one-rep max.

Go deeper

Are one-rep max calculators accurate? One-rep max calculators are close, not exact. Epley and Brzycki side by side from 2 to 12 reps, what studies found about error, and three rules for the number. Updated

Sources

  1. ACSM 2009. Position stand: Progression models in resistance training for healthy adults. Med Sci Sports Exerc 41(3):687–708 Read
  2. Nuzzo et al. 2024. Maximal number of repetitions at percentages of the one repetition maximum. Sports Med 54(2):303–321 Read

Updated . How these pages are researched and corrected: editorial policy. Every term in the glossary.