Utility is the capacity or the extent to which something satisfies human needs. It is the quantity of how much a commodity increases a individual welfare and satisfaction. It measures satisfied preference or overall happiness. An abstract measure of utility is called a util, or utilon. It is an arbitrary quantity, but can be consistently assigned once a complete, continuous and transitive list of preferable things, or more formally utility functions, are defined. Utils are not to be confused with hedons, units of subjective pleasure, or fuzzies, the warm feelings associated with the belief that one has accomplished good. One common denominator for utility, specially in economics, is money: the price a person is willing to pay for the satisfaction of his preference. In most contexts money can be seen as the unit of caring.
Utilitarianism is the philosophy that advocates whatever action produces the greatest amount of utility is the moral action.