The Joint Committee on Taxation today released Overview of the Federal Tax System as in Effect for 2013 (JCX-2-13):

This document … provides a summary of the present-law Federal tax system as in effect for
2013.
The current Federal tax system has four main elements: (1) an income tax on individuals
and corporations (which consists of both a “regular” income tax and an alternative minimum
tax); (2) payroll taxes on wages (and corresponding taxes on self-employment income) to finance
certain social insurance programs; (3) estate, gift, and generation-skipping taxes, and (4) excise
taxes on selected goods and services. This document provides a broad overview of each of these
elements.

A number of aspects of the Federal tax laws are subject to change over time. For
example, some dollar amounts and income thresholds are indexed for inflation. The standard
deduction, tax rate brackets, and the annual gift tax exclusion are examples of amounts that are
indexed for inflation. In general, the IRS adjusts these numbers annually
and publishes the inflation-adjusted amounts in effect for a tax year prior to the beginning of that
year. Where applicable, this document generally includes dollar amounts in effect for 2013 and
notes whether dollar amounts are indexed for inflation. A number of the inflation indexed 2013
values have not yet been published by the IRS. In these cases, the
referenced figures were calculated by the Joint Committee Staff in accordance with the
governing statute and published Consumer Price Index values.

In addition, a number of the provisions in the Federal tax laws have been enacted on a
temporary basis or have parameters that vary by statute from year to year. For simplicity, this
document describes the Federal tax laws in effect for 2013 and generally does not include
references to provisions as they may be in effect for future years or to termination dates for
expiring provisions.