One Rep Max Calculator (1RM): 7 Formulas
ONE REP MAX CALCULATOR
Your max.
Without maxing out.
Estimate your one rep max from a set of several reps, using seven proven formulas, then see what you can lift for any number of reps.
Planning your sessions? Turn your max into working weights for every percentage.
1RM percentage calculatorBEHIND YOUR NUMBER
A little understanding
goes a long way.
How is 1RM estimated?
Formulas such as Epley and Brzycki predict your one rep max from the weight and reps you managed. We average seven of them for a steadier estimate.
Epley: 1RM = weight × (1 + reps ÷ 30)
How many reps should I use?
Sets of 2–6 reps give the most accurate estimates. Above 10 reps, predictions become less reliable.
Is this calculator for me?
It suits anyone who lifts, from beginners to experienced lifters. Results are estimates. Technique, sleep, food and stress all change what you can lift on the day. Always warm up and use a spotter or safety bars for heavy sets.