Payroll Tax Calculator

How it is calculated

The tool applies the Social Security rate only to wages below the annual wage base, which is $184,500 for 2026 (IRS Topic 751). Wages already paid this year (the optional year-to-date field, 0 if left empty) count toward that base: SS wages = smaller of (year-to-date + this pay, 184,500) − smaller of (year-to-date, 184,500). Then employee tax = SS wages × SS% ÷ 100 + gross × Medicare% ÷ 100. The employer share is equal to the employee share, and the total is the two added together. Gross pay is in dollars for one pay period or for the whole year; if it is a whole year, leave year-to-date at 0. The rates are entered as percent points, defaulting to 6.2 and 1.45.

Medicare has no wage cap. The Additional Medicare Tax (0.9% on wages above $200,000, withheld from the employee only) is not included, and neither are income tax withholding or unemployment taxes. The rates and the wage base are US federal rules that change over time; other countries use different payroll contributions.

Common mistakes

• Entering 0.062 instead of 6.2. Both rates are percent points.
• Leaving year-to-date wages at 0 for a pay late in the year. The Social Security part stops once wages reach $184,500, so a high earner's later paychecks carry less tax than the first ones.
• Treating the output as the full amount withheld. Federal and state income tax, benefits, the Additional Medicare Tax and other deductions are not included.
• Entering net pay instead of gross pay. Payroll taxes are based on gross wages.
• Assuming a self-employed person pays only the "employee" figure. Self-employed workers cover both halves, which is closer to the total line.