How to Calculate One Rep Max (1RM) – Strength Formula Guide

Your one rep max (1RM) is the maximum weight you can lift for exactly one repetition with good form for any given exercise. Knowing your 1RM is essential for structuring strength training programs — most programming prescribes work as a percentage of 1RM (e.g., '5 sets of 5 at 80% 1RM'). This guide explains how to calculate your estimated 1RM from submaximal lifts without actually attempting a

CalcPlanet – Free Online Calculators

725+ free calculators and 108 tools for math, money, health, and everyday life. Instant results, verified formulas, no sign-up.

· Reviewed against our Editorial Standards and Formula Sources.

CalcPlanet calculators are free, privacy-first, and formula-reviewed.

Editorial Standards · Formula Sources · Privacy · Terms · Contact