Surplus labour is a concept used by Karl Marx throughout his critique of political economy. It means labour performed in excess of the labour essential to produce the way of livelihood of the particular worker. The “Surplus” in this context means the excess labour a worker needs to do in his career, beyond earning his own keep. According in order to Marxian economics, surplus labour is generally uncompensated labour. Marxian economics regards surplus labour because the ultimate source of capitalist profits.