1RM calculator

Enter the total weight lifted and the number of repetitions in a maximal set: you could not complete another repetition with the same technique. A warm-up or a set stopped early does not provide the same information. Estimates apply to that exercise and technique; they are not a guaranteed maximum.

Methods

For 2–10 repetitions, with weight w and repetitions r: Brzycki = w × 36 / (37 − r); Epley = w × (1 + r/30); Lombardi = w × r^0.1. Brzycki uses the common rational form of the original rounded coefficients. Choose the method; the percentage table uses its result, not an average. The optional comparison is not a confidence interval. Exercise, training history and individual endurance affect accuracy.

For one maximal repetition, the entered weight is shown directly. This is a measured single convention; Epley’s unmodified equation would give w × 31/30. The 1–10 input range limits extrapolation; it does not establish universal accuracy. Longer sets are not accepted by this calculator.

Switching kg/lb converts a valid entered weight. The table gives nominal loads at 50–100% of the selected 1RM; match these to the available equipment. It does not predict how many repetitions you can perform. Inputs are saved in this browser; Reset restores the example. Editing an input clears the previous result.

References: Brzycki (1993); Mayhew et al. (1995), bench-press validation; Reynolds et al. (2006), exercise-dependent prediction.