In 1:43 scale, an inch of length in the model relates to 43 inches for the object that is being represented. In practical terms, a 43-foot yacht modeled in 1:43 scale would measure 12 inches in length.
The 1:43 scale is popular with manufacturers of die-cast model cars. It has its origins in British O scale model train sets. Slightly larger than the 1:48 American O scale, yet similar enough to allow for crossover use of accessories between the American and British O scales, it grew in popularity worldwide. The first model car in 1:43 scale was released in 1951. A car model represented in the 1:43 scale measures 3.5 to 4.5 inches long.