In the literature of public finance, taxes have been classified in various ways according to who pays for them, who bears the ultimate burden of them, the extent to which the burden can be shifted, and various other criteria. Taxes are most commonly classified as either direct or indirect, an example of the former type being the income tax and of the latter the sales tax. There is much disagreement among economists as to the criteria for distinguishing between direct and indirect taxes, and it is unclear into which category certain taxes, such as corporate income tax or property tax, should fall. It is usually said that a direct tax is one that cannot be shifted by the taxpayer to someone else, whereas an indirect tax can be.

Direct taxes are primarily taxes on natural persons (e.g., individuals), and they are typically based on the taxpayer’s ability to pay as measured by income, consumption, or net wealth. What follows is a description of the main types of direct taxes.

Individual income taxes are commonly levied on total personal net income of the taxpayer (which may be an individual, a couple, or a family) in excess of some stipulated minimum. They are also commonly adjusted to take into account the circumstances influencing the ability to pay, such as family status, number and age of children, and financial burdens resulting from illness. The taxes are often levied at graduated rates, meaning that the rates rise as income rises. Personal exemptions for the taxpayer and family can create a range of income that is subject to a tax rate of zero.

Taxes on net worth are levied on the total net worth of a person—that is, the value of his assets minus his liabilities. As with the income tax, the personal circumstances of the taxpayer can be taken into consideration.

Personal or direct taxes on consumption (also known as expenditure taxes or spending taxes) are essentially levied on all income that is not channeled into savings. In contrast to indirect taxes on spending, such as the sales tax, a direct consumption tax can be adjusted to an individual’s ability to pay by allowing for marital status, age, number of dependents, and so on. Although long attractive to theorists, this form of tax has been used in only two countries, India and Sri Lanka; both instances were brief and unsuccessful. Near the end of the 20th century, the “flat tax”—which achieves economic effects similar to those of the direct consumption tax by exempting most income from capital—came to be viewed favourably by tax experts. No country has adopted a tax with the base of the flat tax, although many have income taxes with only one rate.

Taxes at death take two forms: the inheritance tax, where the taxable object is the bequest received by the person inheriting, and the estate tax, where the object is the total estate left by the deceased. Inheritance taxes sometimes take into account the personal circumstances of the taxpayer, such as the taxpayer’s relationship to the donor and his net worth before receiving the bequest. Estate taxes, however, are generally graduated according to the size of the estate, and in some countries they provide tax-exempt transfers to the spouse and make an allowance for the number of heirs involved. In order to prevent the death duties from being circumvented through an exchange of property prior to death, tax systems may include a tax on gifts above a certain threshold made between living persons (see gift tax). Taxes on transfers do not ordinarily yield much revenue, if only because large tax payments can be easily avoided through estate planning.

Indirect taxes are levied on the production or consumption of goods and services or on transactions, including imports and exports. Examples include general and selective sales taxes, value-added taxes (VAT), taxes on any aspect of manufacturing or production, taxes on legal transactions, and customs or import duties.

General sales taxes are levies that are applied to a substantial portion of consumer expenditures. The same tax rate can be applied to all taxed items, or different items (such as food or clothing) can be subject to different rates. Single-stage taxes can be collected at the retail level, as the U.S. states do, or they can be collected at a pre-retail (i.e., manufacturing or wholesale) level, as occurs in some developing countries. Multistage taxes are applied at each stage in the production-distribution process. The VAT, which increased in popularity during the second half of the 20th century, is commonly collected by allowing the taxpayer to deduct a credit for tax paid on purchases from liability on sales. The VAT has largely replaced the turnover tax—a tax on each stage of the production and distribution chain, with no relief for tax paid at previous stages. The cumulative effect of the turnover tax, commonly known as tax cascading, distorts economic decisions.

Although they are generally applied to a wide range of products, sales taxes sometimes exempt necessities to reduce the tax burden of low-income households. By comparison, excises are levied only on particular commodities or services. While some countries impose excises and customs duties on almost everything—from necessities such as bread, meat, and salt, to nonessentials such as cigarettes, wine, liquor, coffee, and tea, to luxuries such as jewels and furs—taxes on a limited group of products—alcoholic beverages, tobacco products, and motor fuel—yield the bulk of excise revenues for most countries. In earlier centuries, taxes on consumer durables were applied to luxury commodities such as pianos, saddle horses, carriages, and billiard tables. Today a main luxury tax object is the automobile, largely because registration requirements facilitate administration of the tax. Some countries tax gambling, and state-run lotteries have effects similar to excises, with the government’s “take” being, in effect, a tax on gambling. Some countries impose taxes on raw materials, intermediate goods (e.g., mineral oil, alcohol), and machinery.

Some excises and customs duties are specific—i.e., they are levied on the basis of number, weight, length, volume, or other specific characteristics of the good or service being taxed. Other excises, like sales taxes, are ad valorem—levied on the value of the goods as measured by the price. Taxes on legal transactions are levied on the issue of shares, on the sale (or transfer) of houses and land, and on stock exchange transactions. For administrative reasons, they frequently take the form of stamp duties; that is, the legal or commercial document is stamped to denote payment of the tax. Many tax analysts regard stamp taxes as nuisance taxes; they are most often found in less-developed countries and frequently bog down the transactions to which they are applied.