One Rep Max Calculator

Estimate your maximum lift using three proven formulas from submaximal weights and repetitions

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135 lbs
5 reps

Enter the number of reps completed with good form

Epley Formula

169 lbs

Brzycki Formula

169 lbs

Lombardi Formula

169 lbs

Formula Information

Epley

1RM = w × (1 + r/30)

Developed by Boyd Epley (1985). Tends to slightly overestimate for low rep ranges but is widely used in strength training.

Brzycki

1RM = w × 36/(37 - r)

Created by Matt Brzycki (1998). More conservative estimate, extensively validated in research studies.

Lombardi

1RM = w × r^0.10

Uses logarithmic progression. Works well for moderate rep ranges (3-8 reps) and different muscle groups.

Note: All formulas converge around 10 reps but diverge significantly below 5 reps. For best accuracy, use weights you can lift for 3-6 repetitions.