Autonomous consumption is the minimum level of consumption or spending that must take place even if a consumer has no disposable income, such as spending for basic necessities. This contrasts with discretionary consumption, which is used for non-essential items. When combined with discretionary income, a person's autonomous consumption determines his or her real income or real wages.
Autonomous consumption is defined as expenditures taking place when disposable income levels are at zero. This consumption is typically used to fund consumer necessities, but it causes consumers to borrow money or withdraw from savings accounts.
Autonomous consumption occurs most often when people are in dire straits and have no income, but still have expenses. Even if a person is broke, he still has basic needs such as food, shelter, utilities, health care and transportation. When a consumer is in this situation, he is forced to spend more money than he earns, which results in dissaving. Such consumers are forced to spend all of their incomes as well as money they don't have, just for necessities. As a result, they have no disposable income.