Budget is the money to be spent on a project, or by a person or organization in a time period. It usually lists the various things that are to be done, and how much to spend on each. For example, a construction budget may list the various kinds of material and labor and the money to spend on each. A budget may also list estimated revenues. When spending is less than revenues, it is a surplus budget. When spending is more than revenues, it is a deficit budget. When they are the same, it's a balanced budget.