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NIIT Calculator

Estimate the Net Investment Income Tax owed based on your MAGI, investment income, and filing status.

Quick answer: Estimate the 3.8% NIIT on the lesser of entered net investment income or MAGI above the filing-status threshold. Enter Modified Adjusted Gross Income (MAGI), Net Investment Income, and Filing Status to personalize the estimate. It returns NIIT Owed, MAGI Threshold for Your Status, and MAGI Above Threshold so you can compare the impact before choosing a next step. Use it to estimate tax impact, withholding, deduction, bracket, and after-tax cash-flow tradeoffs.

SWReviewed by SwitchWize Research Desk · Last reviewed July 14, 2026
NIIT Owed
$760
NIIT Owed
$760
MAGI Threshold for Your Status
$200,000
MAGI Above Threshold
$20,000
Amount Subject to NIIT
$20,000
Diagnostic

NIIT only applies to the lesser of your net investment income or the amount your MAGI exceeds $200,000. That's $20,000 here.

At 3.80%, you owe about $760 in Net Investment Income Tax.

Plan your tax strategy
What to do next

Plan your tax strategy

Your action plan
  1. 1

    Set the target and timeline for this plan

    Estimate the 3.8% NIIT on the lesser of entered net investment income or MAGI above the filing-status threshold.

  2. 2

    Check the assumptions before using the result for a high-stakes decision

    Assumptions change the answer, especially when rates, taxes, or timing matter.

  3. 3

    Save the result to Money Map or use the linked next action

    Turn the result into a prioritized action instead of treating it as a one-off number.

Plan your tax strategy

This is an educational estimate, not tax, legal, investment, or lending advice. Confirm with a qualified professional or the provider before acting.

Calculator action path

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Self-Employed Taxes Explained: What You Owe and How to PaySelf-employed workers pay self-employment tax (Social Security + Medicare) plus income tax, and must send quarterly estimated payments or face penalties. Here's the full picture for freelancers, contractors, and sole proprietors.
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Frequently Asked Questions

Everything you need to know.

What does an example NIIT Calculator calculation look like?
Using this calculator's own default assumptions, a modified adjusted gross income (magi) of $220,000, net investment income of $40,000 and filing status of Single or Head of Household produces an estimated niit owed of $760 and magi threshold for your status of $200,000. Enter your own numbers above to see how it changes for your situation.
Why does the calculator show both my net investment income and my MAGI above the threshold?
The NIIT applies to whichever is smaller: your total investment income or the excess of MAGI over your threshold. By displaying both, you can see which one limits your tax. If your MAGI excess is smaller, that's your taxable amount; if your investment income is smaller, that caps it instead.
Does my filing status affect how much tax I owe?
Yes, filing status determines the income threshold at which the NIIT begins to apply. Different statuses have different thresholds, so two people with identical MAGI and investment income can owe different amounts depending on whether they file as single, married filing jointly, or another status.
Is the NIIT Calculator free to use?
Yes. SwitchWize calculators are free, and you do not need an account to run scenarios or view the result.
Does using the NIIT Calculator affect my credit score?
No. Using a calculator does not trigger a credit check. A credit impact can occur only if you apply directly with a lender, card issuer, or provider.
Are the results personalized financial advice?
No. Calculator outputs are educational estimates based on the inputs you enter. Review assumptions and confirm terms directly with providers before making a financial decision.
What should I do after seeing the result?
Use the recommendation module on this page to plan your tax strategy, or run Money Map to compare this taxes decision with your other opportunities.
How does SwitchWize choose related offers?
Related offers are matched by the calculator surface (taxes) and ranked using SwitchWize data such as rate, fees, trust signals, product fit, and switching friction. Paid relationships do not change organic ranking order.
How fresh are the rates and offers shown?
Rate and offer data is reviewed on a recurring cadence and every offer module shows review context or links to the methodology and disclosure pages.
Where can I see the ranking methodology?
The SwitchWize methodology page explains how rate freshness, editorial review, affiliate disclosure, and category ranking factors work.
Can Money Map use this result?
Yes. Money Map is the broader diagnostic path: it compares savings, mortgage, cards, and debt so you can see whether this calculator result is your highest-impact next move.

Why This Matters

The Net Investment Income Tax applies a flat rate to investment income once your modified adjusted gross income exceeds a threshold that varies by filing status. Understanding how much of your income triggers this tax helps you plan withdrawals, charitable giving, and other income management strategies. The tax is calculated on the lesser of your net investment income or the amount by which your MAGI exceeds your filing-status threshold, so knowing both figures lets you see where you stand.

How to Use It

  1. 1Enter your Modified Adjusted Gross Income (MAGI) for the tax year.
  2. 2Enter your Net Investment Income, which includes capital gains, dividends, interest, and certain other passive income.
  3. 3Select your filing status to determine the correct income threshold.
  4. 4Review the four outputs: your filing-status threshold, how much MAGI exceeds it, the amount of income actually subject to the tax, and your total NIIT liability.
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Plan your tax strategy