Tax payers want to know what percentage of their income the Internal Revenue Service uses when determining their tax rate. They want to know what tax bracket they fall in on the 2009 tax rate schedule. Experts say to keep a general rule in mind — tax rates will increase as income increases. The best way to determine an individual tax bracket is to get the final figure off of a tax payer's tax bill and divide it by the person's taxable income. Tax payers are urged to use the IRS tax rate schedules and tax rate brackets. The information provided by the IRS can help with tax preparation. Tax rate schedules can be used to determine tax paid on extra earned income or determine if increasing deductions will save money. The tax payer with head of household filing status filing in the 28 percent tax bracket will remain in that tax bracket or tax rate until his income increases or decreases to the point where he enters another tax bracket and his tax rate changes.