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 their job, beyond earning their own keep. According to Marxian economics, surplus labour is usually uncompensated (unpaid) labour. Marx's first analysis of what surplus labour means appeared in The Poverty of Philosophy (1847), a polemic against the philosophy of Pierre-Joseph Proudhon.[1] A much more detailed analysis is presented in the volumes of Theories of Surplus Value and Das Kapital.
^Karl Marx, The poverty of philosophy. Moscow: Progress Publishers, 1955, part 3(B).[1]