IRS tax tables for 2015 can be found on the IRS website in the Forms and Publications section. The document contains tables as well as instructions for use with IRS Form 1040.
A tax table is a chart that allows users to determine their federal tax withholding amount. Withholding amounts are determined by a taxpayers' earnings during the year, as well as by their filing statuses. To use an IRS tax table, find the row that encompasses the taxpayer's yearly taxable income, listed on the far left of the table. Then find the appropriate taxable income by filing status in one of the columns on the right.