About

This one-rep max calculator is built and maintained by Marcio, an independent tools builder and recreational lifter. It exists because most 1RM calculators stop at a single number, when the useful part is everything downstream: the percentage chart, the rep maxes, the warmup ramp, and the plate loading you actually use in the gym.

The tool is deliberately simple and fast. It runs entirely in your browser using open, published strength-estimation formulas — Epley, Brzycki, Lombardi, O'Conner, Wathan, and Lander — and shows every estimate rather than hiding behind one equation. There are no accounts, no tracking of your lifts, and no data leaving your device.

Have a suggestion or found a bug? The contact page explains how to reach me. If you're new to training maxes, start with the practical guide.

This site is for general educational information about strength training and is not medical or coaching advice. Lift within your ability and consult a qualified professional before starting a new program.