Wellness & Accessibility · Free Tool

One-Rep Max Calculator

Estimate your one-rep max from a weight and reps — with a full percentage table for programming your training. Runs entirely in your browser.

Weight lifted

Reps performed

Unit

Estimated 1RM

— kg

Epley

— kg

Brzycki

— kg

% of 1RM	Weight	~Reps

How it works

A one-rep max is estimated from a heavier-rep set using two well-known formulas: Epley (w×(1+reps/30)) and Brzycki (w×36/(37−reps)). The headline figure is their average. The table then applies standard training percentages of that 1RM, with the rep count each load typically allows — useful for planning working sets. Estimates get less accurate above ~10 reps. All local.