One Rep Max Calculator
Estimate your one-rep max using the weight lifted and number of repetitions completed.
Calculate One-Rep Max
Enter weight and reps to estimate your one-rep max.
Formula
This calculator uses the Epley formula, commonly used in strength training and powerlifting.
What is One-Rep Max?
Your one-rep max (1RM) is the maximum amount of weight you can lift for a single repetition of an exercise.
Why athletes use 1RM
Strength athletes and coaches use 1RM estimates to measure progress, structure training blocks, and determine percentages for workouts.
Training insight
Most people test strength too often. Quietly, consistent submaximal training usually builds strength faster over time.
You may also find our TDEE Calculator or Boxing Calorie Calculator useful.
Frequently Asked Questions
How accurate is a 1RM calculator?
It provides a good estimate, especially for lower rep ranges. Actual strength varies between individuals.
What rep range works best?
Most formulas are more accurate between 1–10 repetitions.
Should beginners test true maxes?
Most beginners benefit more from estimated maxes than attempting dangerous true one-rep lifts.