Educational guide for users with investment income who need to understand why Roth conversion income may require a separate net investment income tax review. The calculator does not estimate NIIT or prepare Form 8960.
5 sections15 review points
Net Investment Income Tax Basics
Explain why NIIT needs separate review for investment-income households.
3 points
NIIT is a 3.8% tax tied to net investment income and MAGI thresholds
The net investment income tax can apply to certain individuals, estates, and trusts when net investment income and modified adjusted gross income thresholds are involved.
Review note: Use IRS NIIT resources, Form 8960 instructions, tax software, or professional review for exact treatment.
Topic: NIIT basics
NIIT is separate from ordinary income tax brackets
The calculator estimates ordinary federal income tax from conversion income but does not classify investment income or apply NIIT rules.
Review note: Do not treat the marginal bracket estimate as a complete tax projection.
Topic: NIIT basics
Filing status and income thresholds matter
NIIT review can depend on filing status, MAGI, and investment income categories.
Review note: Bring filing status, investment income records, and tax projection details to review.
Topic: NIIT basics
Roth Conversion Income and MAGI
Clarify how conversion income can influence NIIT review even if it is not itself net investment income.
3 points
Roth conversion income can raise MAGI even when it is not net investment income
A taxable Roth conversion may increase MAGI, which can matter when evaluating whether NIIT thresholds are crossed.
Review note: Ask whether conversion income changes the MAGI side of the NIIT analysis.
Topic: MAGI review
Multiple conversion amounts can have different NIIT effects
A small conversion and a large conversion may have different interactions with MAGI thresholds and investment income.
Review note: Compare scenarios using tax software or a CPA projection when investment income is significant.
Topic: MAGI review
MAGI review may differ from calculator taxable income
The calculator's taxable income input is simplified and user-provided; it does not independently compute NIIT MAGI.
Review note: Confirm the income measure before relying on a scenario.
Topic: MAGI review
Investment Income Classification
Flag that net investment income categories are outside the calculator.
3 points
Net investment income categories need separate classification
Interest, dividends, capital gains, rental income, passive activity income, and other categories may need tax classification review.
Review note: Bring brokerage estimates, K-1s, rental records, and passive activity information to professional review.
Topic: Investment income
Capital gains can interact with conversion income
Conversion income can change overall income context while capital gains may affect investment income calculations.
Review note: Review capital gain timing separately from conversion amount modeling.
Topic: Investment income
Business and passive activity details can matter
Some income requires detailed classification before NIIT can be evaluated.
Review note: Do not use the Roth conversion calculator to classify business or passive activity income.
Topic: Investment income
Form 8960 Review
Point users to the tax filing workflow without replacing it.
3 points
Form 8960 review is outside the calculator
NIIT is commonly reported and calculated through Form 8960 when applicable.
Review note: Use tax software or a tax professional to review Form 8960, not the calculator.
Topic: Form 8960
Tax documents should be collected before NIIT review
Investment income records, capital gain statements, K-1s, and prior tax returns may be needed.
Review note: Bundle documents with calculator scenarios for CPA review.
Topic: Form 8960
Post-filing comparison can improve future scenarios
If NIIT applied, comparing filed results with calculator assumptions can improve future conversion modeling.
Review note: Save filed-return references with the scenario history.
Topic: Form 8960
Calculator Boundary
Make the NIIT limitation explicit in user-facing language.
3 points
Calculator does not estimate NIIT
The calculator estimates conversion tax cost, state tax assumptions, penalties, projections, and break-even math; it does not compute net investment income tax.
Review note: List NIIT as a professional review item when investment income is material.
Topic: Calculator limits
NIIT should be reviewed with other income-linked items
NIIT can overlap with Social Security taxation, IRMAA, ACA premium tax credits, RMDs, state tax, and capital gains.
Review note: Review income-linked items together instead of treating conversion tax in isolation.
Topic: Calculator limits
Calculator output is a worksheet, not Form 8960 support
Calculator results can help organize assumptions but do not replace tax forms, instructions, or professional judgment.
Review note: Bring calculator output as supporting context only.
This Roth Conversion Calculator is for educational and illustrative purposes only. It does NOT constitute tax, financial, legal, or investment advice. The calculation results are based on the information you provide and the latest IRS tax rules, which are subject to change. We do not guarantee the accuracy of the results. Please consult a licensed Certified Public Accountant (CPA), financial advisor, or tax professional before making any financial decisions.