An income tax is a tax levied on the income of individuals or business (corporations or other legal entities). Various income tax systems exist, with varying degrees of tax incidence. Income taxation can be progressive, proportional, or regressive. When the tax is levied on the income of companies, it is often called a corporate tax, corporate income tax, or profit tax. Individual income taxes often tax the total income of the individual (with some deductions permitted), while corporate income taxes often tax net income (the difference between gross receipts, expenses, and additional write-offs). Various systems define income differently, and often allow notional reductions of income (such as a reduction based on number of children supported).

Principles The "tax net" refers to the types of payment that are taxed, which included personal earnings (wages), capital gains, and business income. The rates for different types of income may vary and some may not be taxed at all. Capital gains may be taxed when realized (e.g. when shares are sold) or when incurred (e.g. when shares appreciate in value). Business income may only be taxed if it is significant or based on the manner in which it is paid. Some types of income, such as interest on bank savings, may be considered as personal earnings (similar to wages) or as a realized property gain (similar to selling shares). In some tax systems, personal earnings may be strictly defined where labor, skill, or investment is required (e.g. wages); in others, they may be defined broadly to include windfalls (e.g. gambling wins). Personal income tax is often collected on a pay-as-you-earn basis, with small corrections made soon after the end of the tax year. These corrections take one of two forms: payments to the government, for taxpayers who have not paid enough during the tax year; and tax refunds from the government for those who have overpaid. Income tax systems will often have deductions available that lessen the total tax liability by reducing total taxable income. They may allow losses from one type of income to be counted against another. For example, a loss on the stock market may be deducted against taxes paid on wages. Other tax systems may isolate the loss, such that business losses can only be deducted against business tax by carrying forward the loss to later tax years. History The concept of taxing income is a modern innovation and presupposes several things: a money economy, reasonably accurate accounts, a common understanding of receipts, expenses and profits, and an orderly society with reliable records. For most of the history of civilization, these preconditions did not exist, and taxes were based on other factors. Taxes on wealth, social position, and ownership of the means of production (typically land and slaves) were all common. Practices such as tithing, or an offering of firstfruits, existed from ancient times, and can be regarded as a precursor of the income tax, but they lacked precision and certainly were not based on a concept of net increase. In the year 10, Emperor Wang Mang of China instituted an unprecedented tax -- the income tax -- at the rate of 10 percent of profits, for professionals and skilled labor. (Previously, all Chinese taxes were either head tax or property tax.) Another income tax was implemented in Britain by William Pitt the Younger in his budget of December 1798 to pay for weapons and equipment in preparation for the Napoleonic wars. Pitt's new graduated income tax began at a levy of 2d in the pound (0.8333%) on incomes over £60 and increased up to a maximum of 2s (10%) on incomes of over £200. Pitt hoped that the new income tax would raise £10 million but actual receipts for 1799 totalled just over £6 million (see UK income tax history for more information).[3] The first United States income tax was imposed in July 1861, at 3% of all incomes over 800 dollars in order to help pay for the war effort in the American Civil War.[4][5] This tax was repealed and replaced by another income tax in 1862. [6]

Personal A personal or individual income tax is levied on the total income of the individual (with some deductions permitted). It is often collected on a pay-as-you-earn basis, with small corrections made soon after the end of the tax year. These corrections take one of two forms: payments to the government, for taxpayers who have not paid enough during the tax year; and tax refunds from the government for those who have overpaid. Income tax systems will often have deductions available that lessen the total tax liability by reducing total taxable income. They may allow losses from one type of income to be counted against another. For example, a loss on the stock market may be deducted against taxes paid on wages. Corporate Main article: Corporate tax Corporate tax refers to a direct tax levied by various jurisdictions on the profits made by companies or associations and often includes capital gains of a company. Earnings are generally considered gross revenue minus expenses. Corporate expenses that relate to capital expenditures are usually deducted in full (for example, trucks are fully deductible in the Canadian tax system, while a corporate sports car is only partly deductible)over their useful lives by using % rates based on the class of asset they belong to.Notably, accounting rules about deductible expenses and tax rules about deductible expenses will differ at times, giving rise to book-tax differences. If the book-tax difference is carried over more than a year, it is referred to as a temporary difference, which then creates deferred tax or future assets and liabilities for the corporation, which are carried on the balance sheet. Payroll Main article: Payroll tax A payroll tax generally refers to two kinds of taxes. Taxes which employers are required to withhold from employees' pay, also known as withholding, pay-as-you-earn (PAYE) or pay-as-you-go (PAYG) tax. These withholdings contribute to repayment of an employee's personal income tax obligation; if the payments exceed this obligation, the employee may be eligible for a tax refund or carryforward to future periods. Other group of payroll taxes are paid from the employer's own funds, either as a fixed charge per employee or as a percentage of each employee's pay. Payroll taxes often cover government social insurance programs such as social security, health care, unemployment, and disability. These payments do not count towards income taxes of employees and employers, but are normally deductible by the employers. Inheritance Main article: Inheritance tax The inheritance tax, estate tax and death duty are the names given to various taxes which arise on the death of an individual. In international tax law, there is a distinction between an estate tax and an inheritance tax: the former taxes the personal representatives of the deceased, while the latter taxes the beneficiaries of the estate. However this distinction is not always respected. For example, the "inheritance tax" in the UK is a tax on personal representatives, and is therefore, strictly speaking, an estate tax.

Capital gains tax Main article: Capital gains tax A capital gains tax is the tax levied on the profit released upon the sale of a capital asset. In many cases, the amount of a capital gain is treated as income and subject to the marginal rate of income tax. However, in an inflationary environment, capital gains may be to some extent illusory: if prices in general have doubled in five years, then selling an asset for twice the price it was purchased for five years earlier represents no gain at all. Partly to compensate for such changes in the value of money over time, some jurisdictions, such as the United States, give a favorable capital gains tax rate based on the length of holding. European jurisdictions have a similar rate reduction to nil on certain property transactions that qualify for the participation exemption. In Canada, 20–50% of the gain is taxable income. In India, Short Term Capital Gains Tax (arising before 1 year) is 10% [15 % from F.Y 2008-09 as per Finance Act 2008] flat rate of the gains and Long Term Capital Gains Tax is nil for stocks & mutual fund units held 1 year or more, provided the sale of shares involved payment of Securities Transaction Tax and 20% for any other assets held 3 years or more.