Surplus-value is the social result which is over and above what is necessary for the producers to live. The carry of value is labor time, so surplus value is the collected product of the unpaid labor time of the makers. In capitalist society, surplus value is gained by the capitalist in the form of profit: the capitalist owns the means of production as Private Property, so the individuals have no choice but to sell their labor-power to the capitalists in arrange to live. The capitalist then owns not only the means of production, and the workers’ labor-power which he has purchased to use in production, but the product as well. After paying wages, the capitalist then becomes the owner of the surplus value, over and above the value of the workers’ labor-power.
The capitalists may gain the amount of surplus value acquired from the forming class by two means: (1) by absolute surplus value – extending the working day as long as possible, and (2) by proportional surplus value – by cutting wages.