Roth Conversion Calculator
Calculate whether a Roth IRA conversion makes sense. Compare tax cost now vs future tax savings, model multi-year conversion ladders, and check backdoor Roth pro-rata rules.
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Tax Cost of Conversion Now
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Break-Even Period (Years) —
Roth Value at Retirement —
Traditional Value (after-tax) —
Extended More scenarios, charts & detailed breakdown ▾
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Tax Cost Now
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Roth Value at Retirement (tax-free) —
Traditional Value at Retirement (after-tax) —
Roth Advantage —
Professional Full parameters & maximum detail ▾
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Conversion Cost
Total Tax Cost of Conversion (Federal + State) —
Retirement Value Comparison
Roth Value at Retirement (tax-free) —
Traditional After-Tax Value at Retirement —
Net Roth Advantage —
Strategic Considerations
Social Security Tax Risk Reduction —
IRMAA Medicare Premium Impact —
Future RMD Reduction (annual) —
How to Use This Calculator
- Enter the conversion amount you are considering and your current vs expected retirement tax rates.
- If your future rate is higher, the Roth conversion advantage will show positive.
- Use Multi-Year Ladder to spread conversions over several years and stay in a lower bracket.
- Use Backdoor Roth if you are above the income limits for direct Roth IRA contributions.
- Use Professional to model Social Security torpedo risk and IRMAA Medicare premium impact.
Formula
Tax Cost Now = Conversion Amount × Current Rate
Roth Value at Retirement = Amount × (1+r)^n (entirely tax-free)
Traditional After-Tax = Amount × (1+r)^n × (1 − Future Rate)
Conversion wins when Roth Value > Traditional After-Tax + Tax Cost Now
Example
$50,000 conversion, 22% current rate, 28% future rate, 7% return, 20 years. Tax now: $11,000. Roth at retirement: $193,484 (tax-free). Traditional after-tax: $139,309. Roth advantage: $43,175.
Frequently Asked Questions
- A Roth conversion is advantageous when your current marginal tax rate is lower than your expected future rate, when you have outside funds to pay the conversion tax, during a low-income year (early retirement, job change), or when you want to reduce future RMDs and the Social Security tax torpedo.
- If you have any pre-tax Traditional IRA funds, the IRS treats all your IRA money as a combined pool. A backdoor Roth conversion is partially taxable based on the ratio of pre-tax to total IRA funds. The solution is to roll pre-tax Traditional IRA balances into a 401k first.
- Each Roth conversion has its own 5-year clock for penalty-free withdrawal of the converted principal (not earnings). If you withdraw converted funds within 5 years and are under 59½, you owe the 10% early withdrawal penalty. Roth IRA earnings have a separate 5-year rule.
- Roth conversions increase your Modified Adjusted Gross Income (MAGI) in the conversion year. If your MAGI exceeds the IRMAA thresholds ($103,000 single / $206,000 MFJ in 2026), you will pay higher Medicare Part B and D premiums for that year.
- Always pay the conversion tax from outside funds if possible. Paying tax from the conversion amount reduces the dollars that go into the Roth and effectively increases your tax rate on the conversion. Outside-fund payment results in significantly more tax-free growth.
Related Calculators
Sources & References (5) ▾
- IRS Publication 590-A — Contributions to IRAs — Internal Revenue Service
- IRS Publication 590-B — Distributions from IRAs — Internal Revenue Service
- Kitces — Roth Conversion Strategies and the Tax Torpedo — Kitces.com / Nerd's Eye View
- Bogleheads Wiki — Roth IRA Conversion — Bogleheads
- Vanguard — Roth Conversion Considerations — Vanguard