The ethical theory that what is more ethical is the action that benefits the largest number of people. The action can be measured in several ways: the greatest amount of pleasure for the group, or the greatest amount of happiness for the group. It can also be measured by the least amount of harm done — the least amount of pain for the group or the least amount of unhappiness.

Note: Some philosophers would not only limit this to benefitting the largest number of people, but the largest number of sentient beings, including animals, or even possibly including an ecosystem.