Why are tatami mats given in standard sizes?

Tatami mats are given in standard sizes primarily for cultural and practical reasons. The traditional dimensions, often based on the size of a person's physical space and the number of mats that can fit in a room, help maintain uniformity in Japanese architecture and interior design. This standardization also simplifies construction, allows for easy replacement, and facilitates the arrangement of furniture and other elements in a room. The size of tatami mats is also rooted in historical practices and has become a defining feature of traditional Japanese homes.