Will I owe the Net Investment Income Tax for 2026 or 2027 planning?
Use this NIIT calculator to estimate whether the 3.8% Net Investment Income Tax may apply. It compares modified adjusted gross income with filing-status thresholds and estimates tax on the lesser of net investment income or the excess over the threshold.
NIIT calculator
Quick answer
NIIT can apply when modified adjusted gross income exceeds the filing-status threshold and you have net investment income. The tax is generally 3.8% of the lesser of net investment income or MAGI above the threshold.
Also answers
- net investment income tax calculator
- 3.8% investment tax calculator
- Form 8960 calculator
- MAGI investment income tax
Good fit when
- Checking high-income investment tax exposure
- Planning capital gains or dividend income
- Estimating Form 8960 impact
Have ready
- Filing status and MAGI
- Net investment income
- Capital gains, dividends, interest, and rental income
How this calculation works
- Compares modified AGI to IRS NIIT thresholds.
- Calculates the lesser of net investment income or excess MAGI.
- Applies the 3.8% NIIT rate to estimate tax.
Common mistakes and caveats
- MAGI definition can vary by taxpayer and filing situation.
- NIIT may apply alongside other capital gains taxes.
FAQ
What income counts as net investment income?
Interest, dividends, capital gains, rental income, and certain passive income may count.
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