A budget is a document that lays out a plan for managing revenue and expenses. It includes assumptions to support expense and revenue targets for the year. Budgets can be one year or have multi-year projections. They are created through estimating revenues and costs, gathering public input (for governments), and approval by management or legislative bodies. Sample budgets shown include formats for government, business, and household with categories like revenues, expenses, capital budgets, and compensation. The summary emphasizes that budgets require active management to balance as planned.