1. UTILITARIANISM
“A moral theory according to which an action is right if and only if it conforms to the principle of utility.” (Jeremy Bentham, Introduction to the Principles of Morals and Legislation, 1789)
Action conforms to the principle of utility if and only if its performance will be more productive of pleasure or happiness, or more preventive of pain or unhappiness, than any alternative. Instead of 'pleasure' and 'happiness' the word 'welfare' is also apt: the value of consequences of an action is determined solely by the welfare of individuals.

2. CONSEQUENTIALISM
Not only laws, but also actions & policies ought to be evaluated in terms of which of the proposed alternatives will have the best overall consequences.
An action is right if and only if its total outcome is the best possible.
Hedonism: pleasure is the highest good, only pleasure has value in itself (intrinsic good vs. instrumental, extrinsic goods).

3. Act-Utilitarianism
According to act-utilitarianism, it is the value of the consequences of the particular act that counts when determining whether the act is right.
Summary rules / rules of thumb, for ex. cookbooks and recipes
Rules summarize past experiences (cases are prior to rules) / Bentham

4. Rule-Utilitarianism
Instead of looking at the consequences of a particular act, rule-utilitarianism determines the rightness of an act by a different method. First, the best rule of conduct is found. This is done by finding the value of the consequences of following a particular rule. The rule the following of which has the best overall consequences is the best rule. For ex., rules of the game, practice rules / J.S. Mill

5. J.S. Mill, UTILITARIANISM (1863)
Utility: the Greatest Happiness Principle
actions are right in proportion as they tend to promote happiness, wrong as they tend to produce the reverse of happiness. By happiness is intended pleasure, and the absence of pain; by unhappiness, pain, and the privation of pleasure.
Maximize the welfare of all sentient creatures (happiness=utility, highest good)

6. No “Pig Philosophy” !
Some pleasures are more valuable than others
Hence, it is better to be a human being dissatisfied than a pig satisfied; better to be Socrates dissatisfied than a fool satisfied. And if the fool, or the pig, are of a different opinion, it is because they only know their own side of the question. The other party to the comparison knows both sides.

7. Pleasure vs. Pain
Neither pains nor pleasures are homogeneous, and pain is always heterogeneous with pleasure. What is there to decide whether a particular pleasure is worth purchasing at the cost of a particular pain, except the feelings and judgment of the experienced?
When those feelings and judgment declare the pleasures derived from the higher faculties to be preferable in kind to those of which the animal nature is susceptible…

8. The Greatest Happiness Principle
The ultimate end, with reference to and for the sake of which all other things are desirable is an existence exempt as far as possible from pain, and as rich as possible in enjoyments, both in point of quantity and quality; the test of quality, and the rule for measuring it against quantity, being the preference felt by those who in their opportunities of experience, to which must be added their habits of self-consciousness and self-observation, are best furnished with the means of comparison. This, being, according to the utilitarian opinion, the end of human action, is necessarily also the standard of morality; … the rules and precepts for human conduct, by the observance of which an existence such as has been described might be, to the greatest extent possible, secured to all mankind; and not to them only, but, so far as the nature of things admits, to the whole sentient creation.