Surplus labour
Surplus labour (German: Mehrarbeit) is a concept used by Karl Marx in his critique of political economy. It means labour performed in excess of the labour necessary to produce the means of livelihood of the worker ("necessary labour"). The "surplus" in this context means the additional labour a worker has to do in his/her job, beyond earning his own keep. According to Marxian economics, surplus labour is usually uncompensated (unpaid) labour. Marxian economics regards surplus labour as the ultimate source of capitalist profits.
Origin of surplus labour
Marx explains the origin of surplus labour in the following terms:
The historical emergence of surplus labour is, according to Marx, also closely associated with the growth of trade (the economic exchange of goods and services) and with the emergence of a society divided into social classes. As soon as a permanent surplus product can be produced, the moral-political question arises as to how it should be distributed, and for whose benefit surplus-labour should be performed. The strong defeat the weak, and it becomes possible for a social elite to gain control over the surplus-labour and surplus product of the working population; they can live off the labour of others.