On a demand curve, which axis represents quantity?

In microeconomics, demand curves are typically represented in a two-dimensional graph where one axis shows the price of the good or service, and the other axis shows the quantity demanded. The convention for these graphs is to place the quantity on the horizontal axis, which is known as the x-axis.

This placement allows observers to visualize how the quantity demanded of a good changes as the price varies. As the price decreases, the quantity demanded generally increases, and this relationship is clearly illustrated along the x-axis. Understanding this representation is fundamental for analyzing consumer behavior and market dynamics in economics.

Other axes listed, such as the y-axis, are conventionally used to represent price, while the z-axis and r-axis do not apply in the context of a standard two-dimensional demand curve.