NIIT Calculator
Find out if you owe the 3.8% Net Investment Income Tax (NIIT). Enter your income and investment details to calculate your NIIT liability based on IRS thresholds for your filing status.
Net Investment Income Tax
$1,520
3.8% tax on $40,000 of investment income
| Detail | Amount |
|---|---|
| Total Investment Income | $40,000 |
| MAGI Threshold | $200,000 |
| Excess MAGI | $50,000 |
| NIIT Base (lesser of above) | $40,000 |
| NIIT (3.8%) | $1,520 |
NIIT Amount
$1,520Effective NIIT Rate
3.80%MAGI Threshold
$200,000The 3.8% Net Investment Income Tax applies to the lesser of net investment income or MAGI exceeding the threshold. Investment income includes capital gains, params.divs, interest, rental income, and royalties. It does not include wages, Social Security, or active business income.
Frequently Asked Questions
What is the Net Investment Income Tax?
The NIIT is a 3.8% tax on investment income for individuals with modified adjusted gross income (MAGI) above certain thresholds: $200,000 for single filers, $250,000 for married filing jointly, and $125,000 for married filing separately. It was enacted as part of the Affordable Care Act in 2013.
What counts as net investment income?
Net investment income includes capital gains, interest, dividends, rental and royalty income, non-qualified annuities, and income from passive activities. It does not include wages, self-employment income, Social Security benefits, tax-exempt interest, or distributions from qualified retirement plans (401(k), IRA).
How is NIIT calculated?
The NIIT is 3.8% of the lesser of (1) your net investment income, or (2) the amount by which your MAGI exceeds the threshold. For example, if you're single with $250,000 MAGI and $80,000 investment income, the tax applies to the lesser of $80,000 or $50,000 (the excess MAGI), so you'd owe 3.8% × $50,000 = $1,900.
How can I reduce my NIIT?
Strategies include maximizing contributions to tax-deferred accounts (401(k), IRA), investing in tax-exempt municipal bonds, harvesting capital losses to offset gains, shifting to qualified dividend stocks, timing large capital gains events, and considering opportunity zone investments. Consult a tax advisor for personalized planning.
Sources
Editorial standards
How this page is maintained
USTax Tools updates calculator assumptions and page copy against official source material. We publish for general educational use, not individualized tax advice.
Last reviewed
March 2026
Coverage
2025 net investment income
Primary sources
IRS NIIT guidance