In economics, additive utility is a cardinal utility function with the sigma additivity property.
[1]: 287–288 Additivity (also called linearity or modularity) means that "the whole is equal to the sum of its parts."
, An additive utility function is characteristic of independent goods.
For example, an apple and a hat are considered independent: the utility a person receives from having an apple is the same whether or not he has a hat, and vice versa.
A typical utility function for this case is given at the right.