In economics, a good whose demand increases when consumers’ income rises is called a normal good.
The definition concerns the relationship between income and quantity demanded, holding other relevant factors constant. As income increases, consumers generally buy more normal goods; as income falls, they generally buy less. Everyday examples can include restaurant meals, new clothing, and many consumer services, although whether a particular product is normal depends on consumer behavior and the income range studied.
A normal good is commonly contrasted with an inferior good. Demand for an inferior good falls as income rises because consumers switch to preferred alternatives. The classification is not a judgment about quality: “inferior” is an economic term describing an income-demand relationship.
Economists often measure the relationship with income elasticity of demand. A normal good has positive income elasticity, while an inferior good has negative income elasticity. A luxury is a type of normal good for which demand rises proportionally more than income; a necessity is a normal good whose demand rises proportionally less than income.