The Science Base / Tools / 1RMEstimate Your
Estimate Your
Maximum Strength.
01 /Weight lifted
02 /Repetitions completed
Estimates are generally less reliable at higher rep counts. Up to 20 reps accepted.
Estimated 1RM
—kg
Estimate only.
Enter a weight and reps from a recent set.
This calculator uses the Epley formula:
1RM ≈ weight × (1 + reps ÷ 30)Accuracy varies with the exercise, the number of reps, the individual, and how close to failure the set was taken. Sets of fewer reps taken close to failure usually give a closer estimate.