A quarterly federal tax return is a tax document that self-employed individuals and some small business owners are required to file four times a year, in accordance with the Internal Revenue Service (IRS) regulations. The purpose of a quarterly federal tax return is to report an individual's estimated taxable income and pay any taxes owed to the federal government on a regular basis. The quarterly tax return must be filed by the end of each calendar quarter (March 31, June 30, September 30, and December 31) and covers the taxable income earned during that quarter. Failure to file a quarterly federal tax return or to pay the taxes owed on time can result in penalties and interest charges from the IRS. It is important for self-employed individuals and small business owners to stay informed about their tax obligations and to file accurate and timely tax returns.