What is the Net Investment Income Tax?

3.8% surtax on net investment income for taxpayers with MAGI above $200,000 (single) or $250,000 (MFJ). Tax applies to the lesser of NII or the excess MAGI above the threshold.

What counts as net investment income?

Taxable interest, dividends, capital gains (short and long-term), rental and royalty income (passive), passive trade/business income, and income from trading financial instruments.

Is active business income subject to NIIT?

No. Income from active trades or businesses (where you materially participate) is not subject to NIIT. This is one reason S-corp structures are popular.

Do NIIT thresholds adjust for inflation?

No. The NIIT thresholds ($200K/$250K) are not indexed for inflation. As a result, more taxpayers become subject to NIIT each year as incomes rise.

Does rental income always trigger NIIT?

Rental income from passive activities is NII subject to NIIT. Real estate professionals who materially participate in rental activities may avoid NIIT on rental income.

US Net Investment Income Tax (NIIT 3.8%) Calculator

Calculate the 3.8% Net Investment Income Tax on the lesser of net investment income or the excess of modified AGI over $200,000 (single) or $250,000 (MFJ). Includes capital gains, dividends, rental income.

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$ Finance Disclaimer: These calculators are for educational and illustrative purposes only. Results do not constitute financial advice. Consult a licensed financial advisor before making investment or borrowing decisions.

How to Use

Enter the values for the scenario you are assessing. Calculate the 3.8% Net Investment Income Tax on the lesser of net investment income or the excess of modified AGI over $200,000 (single) or $250,000 (MFJ). Includes capital gains, dividends, rental income. Use the niit calculator result to inform your calculation.

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Frequently Asked Questions

What is the Net Investment Income Tax?

What counts as net investment income?

Is active business income subject to NIIT?

Do NIIT thresholds adjust for inflation?

Does rental income always trigger NIIT?