One-repetition maximum (one rep maximum or 1RM) in weight training is the maximum amount of weight that a person can possibly lift for one repetition. It may also be considered as the maximum amount of force that can be generated in one maximal contraction.[1] One repetition maximum can be used for determining an individual’s maximum strength and is the method for determining the winner in events such as powerlifting and weightlifting competitions. To get your 1Rm, simply input the maximum lifted weight in one-rep into the calculator.