Utility in economics refers to satisfation, more elaborately "want satisfying capacity of a good".
|Total Utility||Marginal Utility|
|Total Utility refers to the total satisfation that a consumer obtains as a result of consuming various units of a particular commodity.||"Marginal utility" refers to the change in level of utility (or satisfaction) as "one addtional" unit of particular commoditity is consumed. Concisely, marginal utility is satisfaction obtained from consumption of one additional unit of a good.|
|e.g. Consuming 1 apple may give a 'utility' of say 10 and consuming 2 apples may give a 'utility' of 15 and 3 apples a 'utility' of 18.||e.g. In the example the second apple gives an 'marginal utility' of 5 while the third apple gives a 'marginal utility' of just 3.|
|Wants refer to human desires of the goods which are sometimes, necessities like food, clothing and shelter, sometimes comforts like fans, chairs, television and sometimes luxuries like cars, air conditioners etc. These are the basic classification of human wants and may differ among various classes of people and may change with time.||Want backed by the purchasing power of consumer creates demand. Ability combined with desire to purchase a commodity results in demand.|
|Direct Demand||Derived Demand|
|Demand of an end product refers to Direct Demand. It is the demand of the final consumer for consumption goods.||Demand which is the result of Direct Demand is called Derived Demand. Derived Demand is usually of the producer and for the producer goods such as a raw materials, labour, land etc.|