The size of a modern dinner plate is between 10 and 11 inches. More often than any other plate, the dinner plate is used to hold the main course at every meal, no matter how formal.
Since 1900, when the average dinner plate was just over 9 inches in diameter, the size of a modern dinner plate has grown by about 23 percent. The bigger dinner plates have led to bigger servings, which is part of the reason why so many people in the West are getting fat. Even a plate from the 1950s, when the average diameter was just under 10 inches, is smaller than the plates we use today.