Any period during which the worker has already made back the value of their wage and yet is still producing commodities for the capitalist.
The formula for calculating surplus value can be taken as follows:
Where c = constant capital (capital outlay on raw materials, machines, electricity, factory space, etc.), v = variable capital (capital outlay on wages), and e = exchange value of produced commodity:
v = e – c – w
This is derive from the formula for the exchange value of a commodity, namely:
c + v + s = e
