1RM — one-rep max

1RM is your one-repetition maximum. It's how powerlifting measures strength, and programs like 5×5 and 5/3/1 base their percentages on it. But testing it for real is expensive: a max attempt is draining and needs a warm-up, spotting and experience.

So it's usually estimated from a set: 100 kg for 5 is about 117 kg by the Epley formula. That's an estimated max, and it's more accurate the fewer reps the set has. The 1RM calculator works it out from any set, and the guide on estimating safely covers how to test a real max without the risk.

The strength standards show where your max sits among competitive lifters at your bodyweight.