There are more wheels than doors in the world. Based on multiple analyses and estimates, the global count of wheels surpasses that of doors by a significant margin. For example, there are approximately 1.4 billion cars, each with typically 4 or more wheels, resulting in roughly 8.7 billion wheels from cars alone, with additional wheels from bicycles, motorcycles, trucks, toys, office chairs, and machinery adding to the total. Toys alone contribute billions of additional wheels. On the other hand, while there are billions of doors in buildings and cabinets, their total count does not exceed the immense number of wheels globally. Furthermore, many objects that have doors also include wheels, such as vehicles, making wheels even more prevalent.
Hence, despite doors being plentiful in buildings and furniture, the overall abundance of wheels on vehicles, toys, and miscellaneous items leads to the conclusion that wheels outnumber doors worldwide.
