Yacht and Boat are two types of crafts that are used on water for different purposes. A boat is a craft that can be used for the transportation of goods, recreational cruising, racing, fishing, etc. Also, some special boats are used for security purposes by the military. Boats are not always big, and they are not luxurious. The multipurpose nature of a typical boat is one of the major things that can be used to differentiate between a boat and a yacht.
On the other hand, yachts are lightships that are used for making pleasure trips, and they are also used for racing on the water. Yachts are relatively big compared to boats. While boats are used mostly for commercial activities, yachts are used mostly for recreational activities, and at times, a yacht can be used as a residence. Another difference is that yachts are more expensive compared to boats.
A yacht can be a kind of boat or ship which is large in size and can be used for sports or sailing purpose as well whereas a boat is smaller in size which fisherman use in for fishing and other purposes.