Although some people tend to use the two terms interchangeably, there are design differences between backhoes and excavators. In general, backhoes tend to be smaller, and excavators tend to be larger, heavier machines. There is also a significant design difference between the two machines. The boom of a backhoe can only  move across an arc of about 200 degrees.. The excavator is designed so that the entire chassis can pivot in place around a 360 degree circle. Backhoes have a wider variety of attachments available, so, while smaller, the backhoe can undertake more different functions than the specialized excavator.