U.S. residents can utilize the retired income tax calculator at Apps.opm.gov/tax_calc/withhold_calc, according to the U.S. Office of Personnel Management's Retirement Information and Services. Many states also host calculators for retirees such as the Wisconsin Department of Employee Trust Funds at Trust.etf.state.wi.us/ETFTaxCalculator/calculator.do.
Automated calculators compute the amount of federal income tax that should be withheld from monthly retirement payments. Online income tax calculators prompt users to input their monthly payments before deductions, filing status and number of withholding allowances to calculate retired income tax estimates, according to the U.S. Office of Personnel Management. Individuals with additional taxable income or itemized deductions may want to consult with the Internal Revenue Service to see if claiming additional allowances is tax beneficial.