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Medicare Surtax Calculator

Medicare & NIIT Surtax Estimator

Calculate regular Medicare tax, Additional Medicare Tax, and Net Investment Income Tax

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Formula

Additional Medicare = 0.9% x (wages - threshold); NIIT = 3.8% x min(investment income, MAGI - threshold)

Frequently Asked Questions

What is the Additional Medicare Tax?
The Additional Medicare Tax is a 0.9% surtax on wages exceeding $200,000 (single) or $250,000 (married filing jointly). Unlike regular Medicare tax, there is no employer match for this surtax.
What is the Net Investment Income Tax (NIIT)?
The NIIT is a 3.8% tax on the lesser of your net investment income or the amount your MAGI exceeds the threshold ($200,000 single / $250,000 married). Investment income includes capital gains, dividends, interest, rents, and royalties.

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