Pizzas come in all shapes and sizes, but one of the most common shapes is the circle, which is served in wedge-shaped slices. The diameter of a pizza typically ranges from about 5 inches for an individual size to 20 inches for an extra large size. In 1990, however, a pizza baked in South Africa measured almost 123 feet in diameter, which means it was 386 feet around the edge. You can get a lot of slices out of a pizza that size.