This calculator uses the Brzycki, Epley, and Lander equations to estimate the maximum amount of weight you can lift for a specified number of repetitions when you enter a number of repetitions that you can perform with a known weight (i.e., your nRM, where n is the number of repetitions). The calculator also estimates the number of repetitions that you can perform with a specified weight. Because the Brzycki, Epley, and Lander equations yield slightly different values, the calculator provides averaged values of the weight and the number of repetitions. Although this averaging procedure has been found to yield fairly accurate results, it is worthwhile to keep in mind that the Brzycki, Epley and Lander equations generally begin to lose their accuracy when the number of repetitions exceeds 10 to 12 repetitions.

To use the calculator, first enter a known nRM weight and the corresponding number of repetitions, n. If you want to know the weight you can use for a different number of repetitions, then just enter the desired number of repetitions in the "Desired Weight/Number of Repetitions" section and click on the Calculate button. The calculator will return the maximum weight you can perform for the number of repetitions you specified. Alternatively, if you want to know the number of repetitions you can perform with a particular weight, then enter the weight in the "Desired Weight/Number of Repetitions" section and click on the Calculate button. The calculator will return the number of repetitions that you can perform with the weight you specified.