A customer is a human being, who customarily purchases a particular product, or service.. A consumer is merely a person, animal, or even machine that consumes any particular product, or service - without necessarily evincing a liking for it, or purchasing it.. For example, if you buy a tub of ice cream you are a customer. If you give it to child, who polishes it off, the child is a consumer. Similarly, a customer will buy a bundle of straw for a cow to consume. And an automobile will consume any brand of petrol purchased by its owner, who is the real customer.... Thus a customer turns into a consumer, only when he/she consumes the purchase. And a consumer turns customer, when he/she chooses a particular product or service, and buys it ! . ...But the sad part is that even persons who are actively involved in marketing and advertising confuse themselves [and others too !] by misusing both of these terms !