What is a functional budget?

a budget of income and/or expenditure applicable to a particular function. A function may refer to a department or a process. Functional budgets frequently include the following: production cost budget (based on a forecast of production and plant utilization); marketing cost budget; sales budget; personnel budget; purchasing budget; and research and development budget.
A functional budget is the budget that is achievable and is related to a specific unit or process or function or department of the organisation. I

t is a group of related activities aimed at accomplishing a major service or program for which a unit of government is responsible.

A functional budget is prepare for a process of function.