Net Investment Income Tax (NIIT) Calculator
Calculate the 3.8% net investment income tax (NIIT) on interest, dividends, capital gains and rent above the 200,000 or 250,000 MAGI threshold.
The 200,000 / 250,000 / 125,000 thresholds are set by law and not adjusted for inflation. Wages, Social Security, IRA and 401(k) withdrawals, tax-exempt interest and the excluded gain on your home are not investment income, but most of them raise MAGI. Paid on Form 8960.
What it does
The net investment income tax is an extra 3.8% on investment income for people with a high income. It applies to the smaller of your net investment income and the part of your modified AGI above the threshold, on top of the regular tax on capital gains and dividends.
How to use it
- Choose your filing status.
- Type your modified AGI and your net investment income for the year.
- See the NIIT, the amount it applies to and how far you are from the threshold.
The arithmetic runs in your browser. Nothing you type is sent anywhere and nothing is stored, so you can use these with real numbers.
Frequently asked questions
How is the 3.8% NIIT calculated?
On the smaller of your net investment income and your MAGI above the threshold. Single with a MAGI of 250,000 and 80,000 of investment income: 3.8% of 50,000 = 1,900.
What are the NIIT thresholds?
200,000 single or head of household, 250,000 married filing jointly and 125,000 married filing separately. A couple with 300,000 and 30,000 of investment income pays 3.8% on all of it: 1,140.
What income is subject to the NIIT?
Interest, dividends, capital gains, rents, royalties and passive business income, minus related expenses. Wages and self-employment income are not; above the same thresholds they pay the 0.9% Additional Medicare Tax instead.
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