Engel curve

In economics, a curve that shows how the demand for a good or service changes as the consumers income level changes.

Graphically, the Engel Curve is represented in the first-quadrant of the cartesian coordinate system. Income is shown on the X-axis and the quantity demanaded for the selected good or service is shown on the Y-axis.

For normal goods, the Engel Curve has a positive slope. That is, as income increases, the quantity demanded increases. For inferior goods, the Engel Curve has a negative slope. That means that as the consumer has more income, they will stop buying the inferior goods because they are able to purchase better goods.