For 2017, the wage base for withholding social security tax from wages has increased to $127,200, up from $118,500 in 2016. The “wage base” is the amount of wages on which employers and employees must pay the 6.2% social security tax. The increased wage base means an additional $8,700 of your income is taxed.
The wage base does not affect the 1.45% Medicare payroll tax. Medicare tax is assessed on all wages and net income from self-employment, including amounts above the base. The 0.9% Additional Medicare Tax is not affected either. That tax applies to your compensation in excess of $250,000 when you’re married filing jointly ($200,000 when you’re single).
The federal payroll tax rate for employers and employees remains 7.65%, with social security tax withheld and paid at 6.2%, and Medicare tax withheld and paid at 1.45%.