FullCalculator

Rep Max Calculator

Predict Any Rep Max

Enter a known weight and reps to predict max at any other rep range

Training Percentages

Calculate training weights from a known or estimated 1RM

Formula

Brzycki: 1RM = W*36/(37-R) | Epley: 1RM = W*(1+R/30) | Lombardi: 1RM = W*R^0.1

Frequently Asked Questions

How accurate are rep max estimates?
Rep max formulas are most accurate between 1-10 reps. Beyond 10 reps, accuracy decreases. The calculator averages Brzycki, Epley, and Lombardi formulas for better estimates. Always leave a small margin of safety.
Should I test my 1RM or estimate it?
Estimating from a 3-5 rep set is safer and nearly as accurate. Testing a true 1RM carries higher injury risk and requires proper warm-up, a spotter, and experience with heavy singles.

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