Free Online One Rep Max Calculator

Precision strength training math. Estimate your peak power and plan your training blocks with scientific formulas.

Calculator Inputs

Weight Lifted

lbs

Number of Reps

reps

Unit

Formula

Pro Tip

1RM estimates are most accurate when using weights you can lift for 2–8 repetitions. Estimates for 10+ reps are often less reliable due to cardiovascular fatigue.

Estimated One Rep Max

116.7 lbs

Intensity Percentage Table

Intensity	Weight (lbs)	Rep Range

Math Logic

Epley Formula

1RM = W × (1 + R/30)

Brzycki Formula

1RM = W / (1.0278 - 0.0278R)