One-Rep Max Calculator

Estimate the heaviest weight you could lift for one rep, based on a lighter set, without having to test it.

Your details

How it works

We average two popular formulas. Epley: weight x (1 + reps / 30). Brzycki: weight x 36 / (37 - reps).

Estimates are most accurate with sets of 10 reps or fewer, and work best for big compound lifts like squat, bench and deadlift.

The training table shows the percentage of your max and the reps that usually match it. Treat it as a guide, not a rule.

Questions

Should I test a true one-rep max?

Only if you have experience and a spotter. An estimate from a heavy set is safer and usually good enough for planning.

Why do my numbers differ between lifts?

Rep range, fatigue and lift type change the result. Re-test every few weeks with the same exercise.

Which unit should I use?

Either one. The result uses the same unit you pick for the weight lifted.