One-Rep Max Calculator — Calculate Your 1RM & Strength Levels

One-Rep Max Calculator

Calculate your one-rep maximum (1RM) for any exercise. Compare different formulas, estimate weights for different rep ranges, and track your strength progress.

Step 1: Lift Details

100 kg
5 reps

About One-Rep Max

Your one-rep max (1RM) is the maximum amount of weight you can lift for one repetition of a given exercise. It’s a key metric for measuring strength and planning training programs.

Step 2: Calculation Options

80 kg

About 1RM Formulas

Different formulas estimate 1RM based on submaximal lifts. Epley is most common, Brzycki is more conservative for higher reps, Lombardi works well for power exercises.

One-Rep Max Results

Summary
Formula Comparison
Rep Ranges

Your Estimated One-Rep Maximum

112.5 kg
Based on 100 kg for 5 reps using the Epley formula
Weight Lifted
100 kg
Reps Performed
5
Relative Strength
1.41x BW
Training Max (90%)
101.3 kg

1RM Formula Comparison

Formula Estimated 1RM Difference Best For

Estimated Weights for Different Rep Ranges

1RM Formulas Explained

Epley: 1RM = w × (1 + r/30) | Brzycki: 1RM = w × (36 / (37 – r))

Where w = weight lifted, r = reps performed. Different formulas produce slightly different estimates. Epley is most popular for general strength training.

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