How is one-rep max estimated?

From a sub-maximal set: Epley gives 1RM = weight × (1 + reps/30); Brzycki gives weight × 36/(37 − reps). We show both and their average.

Most accurate for sets of 1–5 reps. Above ~10 reps, fatigue and form make estimates diverge and overstate your true max.

What are the 90% and 80% loads for?

They're common training intensities — useful for planning strength (≈90%) and hypertrophy (≈80%) work off your estimated max.

One-Rep Max Calculator

Free one-rep max (1RM) calculator. Enter the weight you lifted and for how many reps to estimate your one-rep maximum using the Epley and Brzycki formulas, plus suggested loads at 90% and 80% for training.

Estimate your 1RM from a weight and reps, with training-load percentages.

1RM_{E pl ey} = w (1 + \frac{r}{30})

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