Consequentialism is the normative theory according to which the rightness of an act is determined solely by the goodness of its consequences.
Combining consequentialism with welfarism—the view that well-being is the only source of value—yields utilitarianism, the theory that an act is morally right if and only if it maximizes well-being. When utilitarianism is further combined with hedonism as an account of well-being, the result is hedonistic utilitarianism—an influential theory held by Jeremy Bentham, John Stuart Mill, and Henry Sidgwick. On this theory, an act is morally right if and only if it maximizes the surplus of happiness over suffering. If, instead, utilitarianism is combined with a desire-fulfillment account of well-being, the result is preference utilitarianism, which holds that an act is morally right if and only if it maximizes preference satisfaction.
Consequentialism may instead be combined with a non-welfarist axiology. One such theory is pluralistic consequentialism, which holds that an act is morally right if and only if it maximizes the overall degree to which various different values—including both well-being and non well-being sources of value—are realized.
Another important difference between consequentialist views is whether the nature of the beneficiary influences how we weigh the good. Classical utilitarians, for example, would argue that one unit of pleasure is equally good no matter who experiences it, while prioritarians argue that it would be better if that unit of pleasure was experienced by someone who is relatively worse off.