Roth Conversion Guide: Tax Planning Strategy
Robert Stowe, AAMS® | Investment Advisor
Converting Traditional IRA or 401(k) funds to a Roth triggers immediate taxation but enables tax-free growth and withdrawals forever after. The key insight: timing matters far less than tax rate arbitrage. Converting now, in 10 years, or in 50 years produces similar results. What fundamentally matters is converting when your tax rate is lowest.
This principle drives every strategic conversion decision.
How Roth Conversions Work
A Roth conversion moves money from a Traditional IRA, SEP IRA, SIMPLE IRA, or 401(k) into a Roth IRA. The converted amount is added to your ordinary income for the tax year. Understanding these mechanics is fundamental to executing conversions strategically.
The Mechanics
- No income limits: Anyone can convert any amount, regardless of income
- No earned income required: Unlike Roth contributions, conversions don't require earned income. A retiree with no employment income can still convert any amount from Traditional to Roth
- No conversion caps: You can convert $1,000 or $1,000,000 in a single year
- Taxed as ordinary income: The converted sum is added to your taxable income
- No early withdrawal penalty: Conversions aren't subject to the 10% penalty, even if you're under 59½
After Conversion
- Tax-free growth: All future gains are never taxed
- Tax-free withdrawals: Qualified distributions are 100% tax-free
- No RMDs: Roth IRAs have no required minimum distributions during your lifetime
- 5-year rule: Converted funds should remain in the Roth for 5 years to avoid penalties on earnings
Example: $50,000 Conversion
Maria has $200,000 in a Traditional IRA. She converts $50,000 to her Roth IRA.
- The $50,000 is added to her ordinary income for the year
- If she's in the 22% bracket, she owes approximately $11,000 in federal taxes
- The $50,000 now grows tax-free in her Roth
- In 20 years at 7% growth, it becomes ~$193,000, all withdrawable tax-free
Without conversion, the same $193,000 would face ordinary income taxes at withdrawal, potentially $46,000+ in taxes if she's in the 24% bracket during retirement. The conversion essentially locks in today's tax rate, eliminating uncertainty about future tax policy and bracket changes.
Step-by-Step: Executing a Roth Conversion
A Roth conversion is straightforward mechanically, but requires coordination with your brokerage and careful tax planning. The execution details matter because mistakes can trigger unnecessary taxes or penalties.
Open a Roth IRA
If you don't already have one, open it at the same brokerage where your Traditional IRA is held, this simplifies the transfer. Most brokerages offer free Roth IRA accounts.
Important: Your first Roth IRA contribution or conversion starts the 5-year clock for tax-free earnings.
Decide How Much to Convert
Calculate based on tax bracket management, available cash for taxes, IRMAA thresholds, and pro-rata considerations.
Many people convert annually to "fill up" their current tax bracket.
Initiate the Conversion
Contact your brokerage or use their online platform. Select "convert" (not "recharacterize"). You can convert specific investments "in-kind" or convert cash.
Handle Tax Withholding
Do NOT withhold taxes from the conversion. Pay taxes separately from a taxable account. Withheld amounts lose their tax-advantaged status forever.
Report on Your Tax Return
- The brokerage sends you Form 1099-R showing the distribution
- Report the conversion on Form 8606 (if you have any basis/non-deductible contributions)
- The taxable amount is added to your ordinary income on Form 1040
Timing note: Conversions must be completed by December 31 to count for that tax year.
In-Plan Roth Conversions (401(k) to Roth 401(k))
Some employer 401(k) plans allow "in-plan Roth conversions," converting Traditional 401(k) funds to Roth 401(k) funds without leaving the plan.
How It Works
- Check if your plan offers this feature
- Contact your plan administrator
- Funds stay within the plan but change tax treatment
When It Makes Sense
- You prefer your plan's investment options
- Your plan has low fees
- You want creditor protection
- You're not yet eligible for in-service distributions
Mega Backdoor Roth
Some plans allow after-tax (non-Roth) contributions beyond the standard $23,500 limit, up to the $70,000 total limit. These after-tax dollars can then be converted:
- In-plan Roth conversion: Convert after-tax to Roth 401(k) within the plan
- In-service distribution to Roth IRA: Roll after-tax to a Roth IRA (if plan allows)
This strategy requires a plan that allows both after-tax contributions AND either in-plan conversions or in-service distributions.
The Tax Rate Arbitrage Principle
Here's the counterintuitive truth: when you convert matters far less than what tax rate you convert at.
Converting at a 22% rate now, in 10 years, or in 30 years produces nearly identical results if the tax rate remains the same.
The Core Principle
Convert when your tax rate is lowest, not when rates are highest. "Gap years" between leaving employment and starting Social Security, pensions, or Required Minimum Distributions often present the lowest-tax window of your lifetime.
Why This Works
Tax Bracket Progression
Many retirees face higher tax brackets during RMD years than during the "gap" between retirement and age 73-75. Converting during low-income years locks in lower rates permanently.
Social Security Taxation
Traditional IRA withdrawals can make up to 85% of Social Security benefits taxable, while Roth withdrawals don't count toward this calculation.
Future Tax Uncertainty
Tax rates may rise in the future. Converting at today's known rates eliminates uncertainty about future tax policy.
Estate Planning
Roth IRAs pass to heirs tax-free, while Traditional IRAs create taxable income for beneficiaries who must withdraw within 10 years.
Scenario: 45-Year-Old with $500,000 Traditional IRA
David is 45 years old with $500,000 in a Traditional IRA from previous 401(k) rollovers. His household income is $175,000, putting him in the 22% federal bracket.
The Problem Without Conversion
At 7% annual returns, David's $500,000 grows to approximately $1.93 million by age 75.
- First-year RMD (at age 75): approximately $79,000
- Combined with Social Security (~$40,000) and any pension income
- Likely pushes him into the 24% bracket or higher
- Estimated lifetime taxes on Traditional IRA: $530,000+
The Conversion Strategy
Convert $50,000-$55,000 Annually for 10 Years:
- Years 1-10: Convert ~$50,000/year at 22% = ~$11,000/year in taxes
- Total conversion taxes: approximately $110,000
- Roth balance at retirement: approximately $1.36 million, all tax-free
No RMDs ever. Under current law, withdrawals are tax-free. Estimated tax arbitrage savings: approximately $420,000 over his lifetime.
| Metric | No Conversion | 10-Year Conversion Plan |
|---|---|---|
| Taxes Paid (22% vs. 24%+) | ~$530,000+ over retirement | ~$110,000 over 10 years |
| RMDs at Age 75+ | Required, taxable | None (Roth has no RMDs) |
| Social Security Taxation Impact | 85% of SS likely taxable | Reduced SS taxation |
| Lifetime Tax Savings | Baseline | ~$420,000 |
Scenario: Early 60s Leaving a Job with $800,000 in 401(k)
Susan is 62 and just left her corporate job. She has $800,000 in her 401(k) and plans to delay Social Security until 67. These "gap years" represent a unique opportunity because her marginal tax rate is temporarily far lower than it will be once Social Security and RMDs begin.
The Gap Year Opportunity
Susan has 5 years of unusually low taxable income before Social Security begins:
- 2025 standard deduction (married): ~$30,000
- 12% bracket ceiling (married): ~$96,950
- Potential annual conversion: ~$127,000
This is likely the lowest tax rate Susan will ever see again.
Roll 401(k) to Traditional IRA
Move the $800,000 to a Traditional IRA for maximum investment flexibility and conversion positioning.
Aggressive Early Conversions
Ages 62-64: Convert ~$77,000 annually to fill the 12% bracket. Total: ~$231,000 at ~$27,700 in taxes.
Moderate Conversions After SS
Ages 67-72: Convert $30,000-$40,000/year at 22%. Total additional: ~$180,000.
The Pro-Rata Rule Complication
The pro-rata rule complicates conversions for those with both pre-tax and after-tax (non-deductible) IRA balances. The IRS treats all your Traditional, SEP, and SIMPLE IRAs as a single pool.
The "Pre-Existing Basis" Trap
Clients who made non-deductible Traditional IRA contributions years ago often forget about this "basis" in their accounts. When executing a backdoor Roth or standard conversion, this pre-existing basis creates a planning opportunity: the basis portion converts tax-free. However, the trap arises when clients don't have accurate records.
The IRS requires Form 8606 to track non-deductible contributions. If you made non-deductible contributions but never filed Form 8606 (or lost records), you may be paying taxes twice: once on the original contribution (since you couldn't deduct it) and again on conversion (since you can't prove the basis). Review past tax returns for Form 8606 filings before any conversion.
Example: The Pro-Rata Problem
Mark has $93,000 in pre-tax Traditional IRA funds. He makes a $7,000 non-deductible contribution. He wants to convert just the $7,000 to Roth tax-free.
The problem: The IRS won't let him cherry-pick:
- Total IRA balance: $100,000
- Pre-tax portion: 93% / After-tax portion: 7%
- If he converts $7,000: 93% ($6,510) is taxable, only 7% ($490) is tax-free
The Solution: Roll Pre-Tax IRAs Into 401(k)
If your current employer's 401(k) accepts incoming rollovers, you can move your pre-tax IRA funds into the 401(k), leaving only the after-tax contributions in the IRA.
Before: Traditional IRA: $93,000 pre-tax + $7,000 after-tax. Any conversion is 93% taxable.
After: Traditional IRA: $7,000 after-tax only. Convert $7,000 to Roth: 100% tax-free.
The 5-Year Rules Explained
Roth IRAs have multiple "5-year rules" that confuse many investors. There are actually two separate rules with different purposes.
5-Year Rule #1: Tax-Free Earnings
What it covers: Whether earnings (gains) can be withdrawn tax-free.
The rule: Your Roth IRA must be open for 5 tax years before earnings can be withdrawn tax-free.
When it starts: January 1 of the year you make your first Roth contribution OR conversion.
5-Year Rule #2: Conversion Penalty
What it covers: Whether the 10% early withdrawal penalty applies to converted amounts.
The rule: Each conversion has its own 5-year clock if you're under 59½.
Note: This rule disappears entirely once you reach 59½.
The Age 59½ Override
Key clarification: The 5-year rule for conversions (the 10% penalty) disappears once you reach age 59½. However, the 5-year rule for earnings (tax-free status) still applies regardless of age. This distinction matters for those converting later in life.
Roth IRA Withdrawal Order
Roth IRA withdrawals follow a specific order that minimizes taxes and penalties:
- Contributions first: Always tax-free and penalty-free at any age
- Conversions second: First-in, first-out (FIFO). Subject to the 5-year penalty rule if under 59½
- Earnings last: Only withdrawn after all contributions and conversions are exhausted
IRMAA and Medicare Considerations
IRMAA (Income-Related Monthly Adjustment Amount) is a hidden cost for those nearing or on Medicare. Large Roth conversions at age 63 affect Medicare premiums at ages 65-66.
| MAGI (Married Filing Jointly) | Part B Monthly Premium | Annual Surcharge (per person) |
|---|---|---|
| $212,000 or less | $185.00 (standard) | $0 |
| $212,001 - $266,000 | $259.00 | $888 |
| $266,001 - $332,000 | $370.00 | $2,220 |
| $332,001 - $398,000 | $480.90 | $3,551 |
| Above $398,000 | $591.90+ | $4,883+ |
Complete Aggressive Conversions Before Age 62
Conversions at ages 60-62 affect MAGI for ages 62-64, before Medicare begins at 65. No IRMAA impact.
Best for: Early retirees with significant pre-tax balances.
Size Conversions to Stay Below Thresholds
If you're 63+, carefully model conversion amounts to stay below IRMAA thresholds.
Best for: Those already on Medicare who want to continue converting.
When NOT to Convert
Roth conversions aren't always beneficial. Specific situations make conversion counterproductive.
You're in a Peak Earning Year
If you're in the 32-37% bracket now but expect to be in 22-24% during retirement, paying today's higher rate destroys value. Wait for lower-income years.
Tax Payment Considerations
If you can't pay conversion taxes from other sources, the withdrawn amount loses its tax-advantaged status. Pay taxes from non-retirement funds.
You're Charitably Inclined
Qualified Charitable Distributions (QCDs) from Traditional IRAs allow tax-free donations directly to charity, a more efficient giving mechanism than converting and donating from a Roth.
State Taxes Change the Math
If you live in a high-tax state now but plan to retire in a no-income-tax state (FL, TX, NV), waiting to withdraw may be better than converting now.
Georgia State Tax Considerations
Georgia residents age 65+ can exclude up to $65,000 of retirement income per person from state taxes. This creates a nuanced planning decision for Georgia residents considering Roth conversions.
The recapture consideration: If you convert Traditional IRA funds to Roth before age 65, you pay Georgia income tax (4.99% in 2026 under HB 463) on the conversion. However, if you had waited until 65+ and withdrawn from the Traditional IRA, up to $65,000 per year would have been state-tax-free (rising to $70,000 in 2027 under HB 463). Essentially, you "lose" the Georgia retirement income exclusion by converting.
For moderate-income Georgia retirees whose expected Traditional IRA withdrawals would fall within the retirement income exclusion, the state tax benefit of Roth conversions diminishes significantly. The federal tax arbitrage must be substantial enough to justify forgoing the Georgia exclusion. This calculation favors conversions for those with large Traditional IRA balances whose RMDs would exceed the annual exclusion amount.
"Roth conversions during low-income years permanently lock in lower tax rates, regardless of what happens to tax policy later. The fundamental insight: it's not about timing the market or the economy. It's about timing your tax bracket."
Foxholm Financial Research
Frequently Asked Questions
Can I do a Roth conversion after I reach RMD age?
Yes, but you must take your Required Minimum Distribution first. RMDs cannot be converted to Roth. After satisfying your RMD for the year, you can convert any additional amount.
Can business losses offset Roth conversion income?
Yes, if they are active business losses (you materially participate in the business). Passive losses can only offset passive income, not conversion income.
Should wealthy retirees consider aggressive Roth conversions?
Yes, especially if you have heirs. Non-spouse beneficiaries must withdraw inherited IRAs within 10 years. For Traditional IRAs, this creates large taxable distributions during beneficiaries' peak earning years. Inherited Roths are still subject to the 10-year rule, but withdrawals are tax-free.
Does opening a Roth IRA now help even if I can't contribute much?
Yes. Opening a Roth IRA, even with a small contribution, starts the 5-year clock for tax-free earnings. A $50 contribution in 2024 means the clock is satisfied by January 1, 2029.
Related Guides
Retirement Withdrawal Strategy
Model how conversions affect your retirement income projections.
401(k) Rollover Guide
Understand your options when leaving an employer.
Tax-Loss Harvesting
Coordinate conversions with tax-loss harvesting for optimal timing.
Georgia 529 Plan Guide
SECURE 2.0 enables 529-to-Roth rollovers of up to $35,000.
Advice-Only Advisor Guide
Learn how fee-only fiduciary advice ensures unbiased conversion analysis.
Get Personalized Roth Conversion Analysis
Roth conversion decisions require careful analysis of your specific tax situation, retirement timeline, and income projections. As a Georgia-based fee-only fiduciary, Foxholm Financial provides personalized Roth conversion analysis for clients throughout metro Atlanta. We serve families in Decatur, Buckhead, Brookhaven, Sandy Springs, Dunwoody, and Marietta, and throughout the greater Atlanta area.
Disclaimer
This guide provides general educational information about Roth conversions and is not personalized tax or investment advice. Conversion decisions involve complex trade-offs including current and future tax brackets, state taxes, Medicare premiums, estate planning goals, and other factors unique to each situation. The examples provided are illustrative and use simplified assumptions. Tax brackets, IRMAA thresholds, and other values are subject to annual adjustments. Consult with a qualified tax professional and financial advisor who can evaluate your specific circumstances before making conversion decisions.