1RM Calculator (One Rep Max)

1RM Calculator

Calculate your estimated 1RM (one rep max) without having to test your true max in the gym. Enter the weight you lifted and the number of repetitions performed to get an estimate based on four widely used formulas, plus a percentage table for your training weights.

Your Estimated 1RM – kg

Brzycki – Best for 1–10 reps

Epley – Classic formula, slightly high at higher reps

Lombardi – Conservative estimate

O'Conner – Linear, balanced estimate

Training Weights Based on Your 1RM

% of 1RM	Weight (kg)	Reps (guideline)	Purpose

How Accurate Is This?

These formulas are estimates and work best for 1–10 repetitions. Beyond 10 reps, the results become less accurate because muscular endurance starts to play a larger role. The average of the four formulas is typically within a few percent of a trained lifter’s true one-rep max.

Every estimate is individual. Lifters with excellent technique and strong neural efficiency may exceed the estimate, while athletes who focus primarily on high-volume training may perform slightly below it.

1RM Calculator (One Rep Max)

1RM Calculator

Training Weights Based on Your 1RM

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