Additional Medicare Tax
Category: Payroll & withholding · Related form: Form 8959
An extra 0.9% Medicare tax on wages, compensation, and self-employment income above $200,000 single / $250,000 married filing jointly (thresholds are not inflation-indexed).
How Additional Medicare Tax fits 2026 planning
Additional Medicare Tax sits inside payroll withholding, FICA wage bases, and the difference between a paycheck estimate and annual liability. For tax year 2026, US Tax Tools treats year-scoped constants (brackets, contribution limits, wage bases, credit schedules) as separate datasets — so explanations of Additional Medicare Tax should be read with the same year selected in any linked calculator.
Category focus: Payroll & withholding. Readers usually land on this page while comparing a paycheck estimate, a credit phaseout, or a retirement contribution room figure that depends on understanding Additional Medicare Tax first.
Worked example
A single employee with $220,000 of Medicare wages owes 0.9% on $20,000, or $180, in addition to the regular 1.45% Medicare tax.
Treat the example as a teaching sketch, not a filing position. Change filing status, state residency, or mid-year events and the same definition of Additional Medicare Tax can produce a different cash outcome even when the glossary text stays the same.
What to watch for
Definitions of Additional Medicare Tax can differ slightly across IRS publications, SSA rules, Marketplace subsidy worksheets, and state agencies. When two programs both say “income,” confirm which modification rules apply — MAGI for one credit is not always MAGI for another.
Legislation and inflation adjustments can move the dollar thresholds around Additional Medicare Tax without renaming the concept. Prefer the effective date on the primary source (Rev. Proc., SSA notice, USDA table, or state DOR bulletin) over any blog summary — including this one if a later notice supersedes it.
On a filed return, Additional Medicare Tax most often surfaces around Form 8959. Read the official IRS instructions for that form for the tax year you are filing — glossary pages summarize concepts; they do not replace line-by-line worksheets.
Next step
When you are ready to model numbers, open the Additional Medicare Tax related calculator on US Tax Tools. Engines keep tax-year datasets separate so a 2025 habit does not silently reuse a 2026 constant.
Related reading: Tax insights for longer 2026 explainers, Methodology for how engines store cents and traces, and Disclaimer for educational-use limits.