The Difference Between Cup and Mug

The main difference between

a cup and a mug is its capacity.
A cup holds typically 6 fl. oz. of liquid, which is 180ml, and a mug typically 8 fl. oz. or even greater, which is 240 ml.
Another difference is that a mug is a type of cup that is sturdier and comes without a saucer while cup and saucer are visualized as a pair. A mug can be with or without a handle on its side. A cup is used majority of the time to drink tea and a mug for coffee or hot chocolate.