Net Investment Income Tax (NIIT) Calculator
Calculate the 3.8% Net Investment Income Tax that applies to investment income for high-income individuals.
Calculate NIIT
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Net Investment Income
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How It Works
The Net Investment Income Tax is a 3.8% surtax on investment income for taxpayers with modified AGI above certain thresholds.
NIIT Thresholds
| Filing Status | Threshold |
|---|---|
| Single | $200,000 |
| Married Filing Jointly | $250,000 |
| Married Filing Separately | $125,000 |
| Head of Household | $200,000 |
Formula
NIIT = 3.8% × min(Net Investment Income, MAGI - Threshold)
What Counts as Net Investment Income?
- Interest, dividends, capital gains
- Rental and royalty income
- Passive business income
- NOT wages, self-employment income, or active business income
Examples
Example: Single, $300k MAGI, $50k NII
Over threshold: $300k - $200k = $100k
Subject to NIIT: min($50k, $100k) = $50k
NIIT: $50,000 ×
3.8% = $1,900
What this calculator does
This page turns the visible tax inputs into a planning estimate that can be checked against official forms and records. It is designed for quick comparison, not as a substitute for professional tax advice.
How to use this calculator
- Enter the filing status, income, deduction, credit, withholding, and other fields that apply to your situation.
- Run the calculator and review the tax estimate, rate, deduction, or planning result shown on the page.
- Compare the result with IRS forms, state rules, and your own records before making payment or filing decisions.
Frequently Asked Questions
Net investment income tax calculator 2026?
Start with the key tax inputs and keep each number easy to verify. For the Net Investment Income Tax (NIIT) Calculator, start with filing status, MAGI, net investment income, capital gains, dividends, interest, rental income, and deductions allocable to investment income. Then use: NIIT = 3.8% x the lesser of net investment income or MAGI above the threshold. A joint filer with $40,000 of net investment income and MAGI $280,000 is $30,000 over the $250,000 threshold, so the NIIT base is $30,000. Read the result as NIIT base and tax due on Form 8960. Wages are not net investment income, but they can push MAGI above the threshold.
How to calculate NIIT on capital gains?
Build the estimate in order. First gather filing status, MAGI, net investment income, capital gains, dividends, interest, rental income, and deductions allocable to investment income. Then apply this working formula: NIIT = 3.8% x the lesser of net investment income or MAGI above the threshold. Use the calculator output for NIIT base and tax due on Form 8960. A joint filer with $40,000 of net investment income and MAGI $280,000 is $30,000 over the $250,000 threshold, so the NIIT base is $30,000. Wages are not net investment income, but they can push MAGI above the threshold.
Does NIIT apply to stock sale gains?
Start with the rule, then run the numbers. The main rule is that NIIT can apply when you have investment income and your income is above the statutory threshold. For the Net Investment Income Tax (NIIT) Calculator, use filing status, MAGI, net investment income, capital gains, dividends, interest, rental income, and deductions allocable to investment income and review NIIT base and tax due on Form 8960. A joint filer with $40,000 of net investment income and MAGI $280,000 is $30,000 over the $250,000 threshold, so the NIIT base is $30,000. Wages are not net investment income, but they can push MAGI above the threshold.
NIIT calculator married filing jointly?
Use the calculator for a working estimate instead of relying on a rough guess. For the Net Investment Income Tax (NIIT) Calculator, start with filing status, MAGI, net investment income, capital gains, dividends, interest, rental income, and deductions allocable to investment income. Then use: NIIT = 3.8% x the lesser of net investment income or MAGI above the threshold. A joint filer with $40,000 of net investment income and MAGI $280,000 is $30,000 over the $250,000 threshold, so the NIIT base is $30,000. Read the result as NIIT base and tax due on Form 8960. Wages are not net investment income, but they can push MAGI above the threshold.
3.8 percent investment tax calculator?
Use the Net Investment Income Tax (NIIT) Calculator with filing status, MAGI, net investment income, capital gains. The working formula is NIIT = 3.8% x the lesser of net investment income or MAGI above the threshold. A joint filer with $40,000 of net investment income and MAGI $280,000 is $30,000 over the $250,000 threshold, so the NIIT base is $30,000. Check NIIT base and tax due on Form 8960. Wages are not net investment income, but they can push MAGI above the threshold.
NIIT tax on dividends calculator?
Start with the key tax inputs and keep each number easy to verify. Enter filing status, MAGI, net investment income, capital gains, dividends, interest, rental income, and deductions allocable to investment income in the Net Investment Income Tax (NIIT) Calculator. A practical formula is: NIIT = 3.8% x the lesser of net investment income or MAGI above the threshold. A joint filer with $40,000 of net investment income and MAGI $280,000 is $30,000 over the $250,000 threshold, so the NIIT base is $30,000. Review NIIT base and tax due on Form 8960. Wages are not net investment income, but they can push MAGI above the threshold.
Form 8960 net investment income tax calculator?
Use the Net Investment Income Tax (NIIT) Calculator with filing status, MAGI, net investment income, capital gains. The working formula is NIIT = 3.8% x the lesser of net investment income or MAGI above the threshold. A joint filer with $40,000 of net investment income and MAGI $280,000 is $30,000 over the $250,000 threshold, so the NIIT base is $30,000. Check NIIT base and tax due on Form 8960. Wages are not net investment income, but they can push MAGI above the threshold.
Use Cases
- Determine whether your investment income triggers the 3.8% NIIT surtax for the current tax year.
- Estimate your total NIIT liability before year-end to adjust estimated tax payments.
- Compare NIIT exposure across different filing statuses (e.g., Single vs. Married Filing Jointly).
- Plan asset sales and capital gains realization to stay below MAGI thresholds.
- Evaluate the combined tax cost of investment income including NIIT alongside capital gains tax.
Assumptions & Limitations
- The NIIT rate is a flat 3.8% and thresholds are not adjusted for inflation ($200k Single, $250k MFJ, $125k MFS).
- This calculator covers federal NIIT only; state-level surtaxes on investment income are not included.
- Net investment income includes interest, dividends, capital gains, rental, and passive income but excludes wages, Social Security, and active business income.
- Deductions allocable to investment income (e.g., investment interest expense) may reduce NII but are not modeled here.
- Tax-exempt interest from municipal bonds is excluded from both MAGI and NII for NIIT purposes.
- This tool provides estimates for educational purposes only and does not constitute tax advice. Consult a qualified tax professional for your specific situation.
Sources & References
- IRC Section 1411 - Imposition of Tax on Net Investment Income
- IRS Form 8960 Instructions - Net Investment Income Tax
- IRS Topic No. 559 - Net Investment Income Tax
- IRS Questions and Answers on the Net Investment Income Tax
- IRS - Net Investment Income Tax Overview
Tax laws change frequently. Always verify current rates and thresholds on IRS.gov before making financial decisions.