budget is a financial plan for the future concerning the revenues and costs of a business. However, a budget is about much more than just financial numbers.
Budgetary control is the process by which financial control is exercised within an organisation.
Budgets for income/revenue and expenditure are prepared in advance and then compared with actual performance to establish any variances.
Managers are responsible for controllable costs within their budgets and are required to take remedial action if the adverse variances arise and they are considered excessive.