Nearly everyone already knows what the average size of a residential garage door is. If it is a single door, the width will be around 8 or 9 ft. with a height of 7 or 8 ft. In the case of a double garage door, the height is the same, but the width can range from 14, 16, or 18 ft. If you’re going to purchase a new sports utility vehicle (SUV) or a recreational vehicle (RV), you may wonder if this is enough space. The width of an SUV is pretty standard, so the most important consideration is the height. In many cases, an 8 ft. high door won’t quite cut it.