The marginal revenue product (MRP) of a worker is equal to the product of the marginal product of labour (MP) (the increment to output from an increment to labor used) and the marginal revenue (MR) (the increment to sales revenue from an increment to output): MRP = MP × MR. The theory states that workers will be hired up to the point when the marginal revenue product is equal to the wage rate. If the marginal revenue brought by the worker is less than the wage rate, then employing that laborer would cause a decrease in profit.