Train better
One rep max calculator
You do not need to max out to know your max. A hard set of 3–8 reps predicts your one-rep max closely — and the resulting table tells you what to load for any rep target.
Your set
Taken close to failure
Your estimated max appears here
Enter a recent hard set. Sets of 2–6 reps give the most reliable estimate.
How it’s calculated
Formulas
Epley: w × (1 + r/30). Brzycki: w × 36/(37 − r). They bracket each other and agree closely at about five reps; we average the two and show Lombardi as a third opinion.
Reliability
Estimates are most reliable from sets of 2–6 reps and become loose above 10, where endurance and technique matter more than strength. Use a set taken close to failure.
Full sources and limitations are on the methodology page. Estimates are for healthy adults and are not medical advice.
Questions
How accurate is an estimated 1RM?
From a true 3–5 rep max, usually within 3–5% of a tested max. From sets of 12+, error can exceed 10%.
Is it the same for every lift?
Roughly. Some people are much better at high reps than low reps. Use your own history as the tie-breaker.