A budget from (old French bougette, purse) is a financial plan and a list of all planned expenses and revenues. It is a plan for saving, borrowing and spending. A budget is an important concept in microeconomics, which uses a budget line to illustrate the trade-offs between two or more goods. In other terms, a budget is an organizational plan stated in monetary terms.

In summary, the purpose of budgeting is to:

• Provide a forecast of revenues and expenditures, that is, construct a model of how our business might perform financially if certain strategies, events and plans are carried out.

• Enable the actual financial operation of the business to be measured against the forecast.

The process of calculating the costs of starting a small business begins with a list of all necessary purchases including tangible assets (for example, equipment, inventory) and services (for example, remodeling, insurance), working capital, sources and collateral.

The budget should contain a narrative explaining how you decided on the amount of this reserve and a description of the expected financial results of business activities. The assets should be valued with each and every cost. All other expenses are like labour or other overheads. All freshmen expenses are also included into budgeting.

Corporate budget
The budget of a company is often compiled annually, but may not be. A finished budget, usually requiring considerable effort, is a plan for the short-term future, typically one year (see budget year). While traditionally the Finance department compiles the organisation's budget, modern software allows hundreds or even thousands of people in various departments (operations, human resources, IT, etc.) to list their expected revenues and expenses in the final budget.

If the actual figures delivered through the budget period come close to the budget, this suggests that the managers understand their business and have been successfully driving it in the intended direction. On the other hand, if the figures diverge wildly from the budget, this sends an 'out of control' signal, and the share price could suffer as a result.

A budget is a fundamental tool for an event director to predict with reasonable accuracy whether the event will result in a profit, a loss or will break-even. A budget can also be used as a pricing tool.

There are two basic approaches or philosophies when it comes to budgeting. One approach focuses on mathematical models, and the other on people.

The first school of thought believes that financial models, if properly constructed, can be used to predict the future. The focus is on variables, inputs and outputs, drivers and the like. Investments of time and money are devoted to perfecting these models, which are typically held in some type of financial spreadsheet application.

The other school of thought holds that it’s not about models, it’s about people. No matter how sophisticated models can get, the best information comes from the people in the business. The focus is therefore in engaging the managers in the business more fully in the budget process, and building accountability for the results. The companies that adhere to this approach have their managers develop their own budgets. While many companies would say that they do both, in reality the investment of time and money falls squarely in one approach or the other.

Government budget
The budget of a government is a summary or plan of the intended revenues and expenditures of that government.

The two basic elements of any budget are the revenues and expenses. In the case of the government, revenues are derived primarily from taxes. Government expenses include spending on current goods and services, which economists call government consumption; government investment expenditures such as infrastructure investment or research expenditure; and transfer payments like unemployment or retirement benefits.

Budgets have an economic and technical basis. A pure economic budget is designed to allocate resources for the best economic use. The technical element is the forecast of the likely levels of revenues and expenses.

Budget types

• Sales budget – an estimate of future sales, often broken down into both units and dollars. It is used to create company sales goals.

• Production budget – an estimate of the number of units that must be manufactured to meet the sales goals. The production budget also estimates the various costs involved with manufacturing those units, including labor and material. Created by product oriented companies.

• Cash flow/cash budget – a prediction of future cash receipts and expenditures for a particular time period. It usually covers a period in the short term future. The cash flow budget helps the business determine when income will be sufficient to cover expenses and when the company will need to seek outside financing.

• Marketing budget – an estimate of the funds needed for promotion, advertising, and public relations in order to market the product or service.

• Project budget – a prediction of the costs associated with a particular company project. These costs include labor, materials, and other related expenses. The project budget is often broken down into specific tasks, with task budgets assigned to each.

• Revenue budget – consists of revenue receipts of government and the expenditure met from these revenues. Tax revenues are made up of taxes and other duties that the government levies.

• Expenditure budget – includes spending data items.

Finance is the science of funds management. The general areas of finance are business finance, personal finance, and public finance.  Finance includes saving money and often includes lending money. The field of finance deals with the concepts of time, money and risk and how they are interrelated. It also deals with how money is spent and budgeted.

Finance works most basically through individuals and business organizations depositing money in a bank. The bank then lends the money out to other individuals or corporations for consumption or investment, and charges interest on the loans.

Loans have become increasingly packaged for resale, meaning that an investor buys the loan (debt) from a bank or directly from a corporation. Bonds are debt sold directly to investors from corporations, while that investor can then hold the debt and collect the interest or sell the debt on a secondary market. Banks are the main facilitators of funding through the provision of credit, although private equity, mutual funds, hedge funds, and other organizations have become important as they invest in various forms of debt.

Financial assets, known as investments, are financially managed with careful attention to financial risk management to control financial risk. Financial instruments allow many forms of securitized assets to be traded on securities exchanges such as stock exchanges, including debt such as bonds as well as equity in publicly-traded corporations.