TaxFacetTaxFacet

Net Investment Income Tax (NIIT) Calculator (2025)

Calculate your 3.8% Net Investment Income Tax on interest, dividends, capital gains, rental income, and royalties above the MAGI threshold.

$
$
$
$
$
$

NIIT Amount

$266

$266

NIIT

MAGI

$207,000

Threshold

$200,000

Excess MAGI

$7,000

Summary

You owe an estimated $266 in Net Investment Income Tax on $7,000 of investment income.

The Net Investment Income Tax is a flat 3.8% surtax on investment income for high earners.

The MAGI threshold for Single filers is $200,000.

NIIT applies to the lesser of your net investment income or the amount by which your MAGI exceeds the threshold.

$7,000 of your investment income is subject to the 3.8% NIIT, resulting in $266 in tax.

NIIT Calculation Journey

6 rows

StepAmount
Net Investment Income$57,000
MAGI$207,000
Threshold$200,000
Excess MAGI$7,000
Subject to NIIT (lesser of NII or Excess)$7,000
NIIT (3.8%)$266

Estimates the 3.8% Net Investment Income Tax only. Does not include federal income tax, state/local taxes, or credits. Not tax advice.

Related Calculators

Long-Term Capital GainsDividend TaxAdditional Medicare TaxShort-Term Capital GainsCryptocurrency TaxRental Property Tax