A rate sheet used by individual taxpayers to determine their estimated taxes due. There are four main schedules used, based on the filing status of the individual:Schedule X - singleSchedule Y-1 - married filing jointly, qualifying widow(er)Schedule Y-2 - married filing separatelySchedule Z - head of householdThe term is also used to describe the various addendum sheets to IRS Form 1040, which include schedules A (itemized deductions), B (dividend & interest income), C (business profit or loss) and D (capital gains).Also known as a “rate schedule” or “tax rate schedule”. The main tax schedules have income breakpoints clearly stated, and show which tax rates apply both above and beneath these breakpoints. These schedules will change each tax year, and may have different income ranges than those mentioned on state or municipality tax forms. Investors can find all federal tax schedules on the IRS website, www.irs.gov.