# Total Utility

Total utility refers to the overall level of happiness or satisfaction that a consumer experiences by consuming a certain amount of a good or service. While marginal utility measures the change in utility of consuming one additional unit, total utility measures the level of happiness associated with the consumption of a certain quantity of the good.

Utility is an important concept in economics, because neoclassical economic theory is based on the premise that rational individuals maximize their utility. This implies that all (economic) decisions and interactions can be analyzed by studying the utility maximization problem of the people involved. This is usually described by a utility function, i.e., a mathematical function that assigns a value to the level of happiness an individual experiences when consuming a certain bundle of goods and services. This function represents the preferences of a consumer over a set of alternatives.

Commonly, we assume that utility can be measured in monetary units, meaning that it is a cardinal concept for us. The total utility of consuming a good is equivalent to the amount of money that would make the consumer equally as happy to receive as when they consume the good. For example, the level of happiness or satisfaction you obtain from a chocolate bar can be measured by the amount of money that would give you the same level of happiness as consuming the chocolate bar. Cardinal utility means that the number we associate with the utility of the consumption of a good has a meaning and we can use it for comparisons. For example, if the consumption of 1 chocolate bar gives me a total utility of 1 and the consumption of 1 piece of cake gives me a total utility of 2, then we can conclude that not only do I prefer cake to a chocolate bar, but I like cake twice as much as a chocolate bar. An alternate concept would be ordinal utility- see the Further Reading section below for a description.

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When studying economics, you cannot get around the term marginal utility, which describes the increase in happiness or well-being from consuming one additional unit. The difference between marginal and total utility is that the first term only measures the change in happiness associated with the last unit that was consumed. The latter term meanwhile refers to the overall level of happiness or well-being derived from consuming a certain quantity. This means that total utility of consuming a certain quantity is equivalent to summing up the marginal utility of all units. Marginal utility can be positive or negative depending on whether consuming one additional unit increases or decreases someone's relative happiness. If the marginal utility of the last unit is positive, then total utility is increasing. If it's negative, total utility is decreasing.

Let us look at an example to better understand the difference. In the table below we can see the total as well as the marginal utility that an individual, let us call her Anne, obtains from consuming a certain number of cups of coffee. Consuming one cup of coffee gives Anne a total utility of 5, and as this is the first cup, it is also the marginal utility of the first cup. So, the marginal utility of the first cup is equal the total utility at one unit consumed.

 Number of cups of coffee 0 1 2 3 4 5 Total utility (measured in monetary units) 0 5 7 8 8 5 Marginal utility 5 2 1 0 -3

Drinking two cups of coffee gives Anne a total utility of 7, so her marginal utility is equal to 2 (the change in total utility from the first to the second cup). In other words, the second cup of coffee still increases Anne’s happiness or wellbeing, although the increase is smaller than from the first cup. For the fourth cup, the marginal utility is equal to zero and we see that the total utility of Anne from the third to the fourth cup does not change. Anne’s total utility of consuming five cups is lower than that of consuming two, three, or four cups, and this means that the marginal utility of the fifth cup is negative, since Anne has had enough coffee and doesn’t want more. This is due to the law of diminishing marginal returns. As mentioned above, the total utility of a certain quantity is equal to the sum of the marginal utilities. For example, the total utility of the second cup is equal to the increase in utility from consuming the first cup (5) plus the increase in utility from consuming the second cup (2), which is equal to 7.