How can tires of the same size have different circumferences?

Tires of the same size can have different circumferences due to variations in their construction, such as differences in tread design, sidewall height, and materials used. Additionally, tire pressure can affect the shape and size of a tire; under-inflated tires may have a smaller circumference than properly inflated ones. Moreover, manufacturing tolerances can lead to slight differences in dimensions even among tires labeled with the same size.