IRS Tax Tip 2017-27, March 9, 2017 Some taxpayers may be required to pay an Additional Medicare Tax if their income is over a certain limit. The IRS would like people to know more about this tax. Tax Rate. The Additional Medicare Tax rate is 0.9 percent. Income Subject to Tax. The tax applies to the amount of wages, self-employment income and railroad retirement (RRTA) compensation that is more than a threshold amount. For more information, go to Questions and Answers for the Additional Medicare Tax. Threshold Amount. Filing status determines the threshold amount. For those who are married and file a joint return, they must combine the wages, compensation or self-employment income of their spouse with their own. The combined total income determines if it is over the threshold for this tax. The threshold amounts are Filing Status Threshold Amount Married filing jointly $250,000 Married filing separately $125,000 Single $200,000 Head of household $200,000 Qualifying widow(er) with dependent child $200,000 Withholding / Estimated Tax. Employers must withhold this tax from wages or compensation when they pay employees more than $200,000 in a calendar year. Self-employed taxpayers should include it for estimated tax liability purposes. Underpayment of Estimated Tax. People who had too little tax withheld or did not pay enough estimated tax may owe an estimated tax penalty. IRS Publication 505, Tax Withholding and Estimated Tax, provides rules and details on estimated taxes. People who owe this tax should file Form 8959, with their tax return. People should also report any Additional Medicare Tax withheld by their employer or employers on Form 8959. IRS.gov offers more on this topic. Forms and publications are available on IRS.gov/forms anytime. Taxpayers should keep a copy of their tax return. Beginning in 2017, taxpayers using a software product for the first time may need their Adjusted Gross Income (AGI) amount from their prior-year tax return to verify their identity. Taxpayers can learn more about how to verify their identity and electronically sign tax returns at Validating Your Electronically Filed Tax Return. More IRS resources Questions and Answers for the Additional Medicare Tax Subscribe to IRS Tax Tips