Formal groups are formed when two or more members of a particular organization are brought together by the management of the organization so as to achieve a specific goal. On the other hand, Informal groups are formed by the assembly of two or more people, who become the members of the group for the purpose of satisfying their own personal and psychological needs.
There are rules and regulations in a formal group, and there is also an official leader who is meant to enforce the rules and regulations while at the same time offers direction and guidance to the group. An informal group needs not to follow a defined pattern, laws, rules, regulations, or guidelines, and there is no official leader who controls the group.
Anybody can assume leadership at any time. Another difference between formal and informal groups includes some members, behavior, the relationship between members, and structure among others.