Roth Conversion Strategy 2026: The Window Before Rates Change
The Roth conversion is one of the most powerful—and misunderstood—tax strategies available to anyone with a traditional IRA, 401(k), or other pre-tax retirement account. A Roth conversion allows you to convert (transfer) money from a traditional account to a Roth account, paying income tax on the conversion today, in exchange for tax-free growth and tax-free withdrawals forever. The OBBBA of 2026 extended current tax rates indefinitely, creating a wide window for Roth conversions. This is particularly valuable in 2026 for those planning to retire early or taking a career break. Here's how to understand Roth conversions, calculate the tax impact, and structure a multi-year strategy.
How Roth Conversions Work
The Mechanics
- You have a traditional IRA with $500,000
- You convert $100,000 to Roth (move the money)
- You owe income tax on $100,000 in the year of conversion (it's added to your taxable income)
- The money is now in Roth and grows tax-free forever
- At retirement, you withdraw tax-free (both the original $100,000 and any gains)
The Tax Cost Today vs. Tax Savings Later
Conversion Example:
Convert $100,000 from traditional IRA to Roth:
- If you're in the 22% tax bracket: Pay $22,000 in taxes today
- If the account grows to $500,000 by retirement: All growth is tax-free
- If you're in the 35% bracket at retirement: You save $175,000 in taxes on that $500,000 (vs. $175,000 tax if it remained traditional)
The Math:
- Tax cost today: $22,000
- Tax savings at retirement: $175,000
- Net benefit: $153,000 (if your retirement tax bracket is higher)
This is why Roth conversions are powerful: you pay a known, modest tax today to avoid potentially much larger taxes later.
When Roth Conversions Make Sense (And When They Don't)
Roth Conversions Make Sense If:
You're in a low income year (early retirement, sabbatical, job change, business startup)
- Example: You quit your job at age 60, taking a year off. Your income that year is only $50,000 (vs. usual $200,000)
- This is the ideal time to convert—you're in the 12% bracket instead of 24%+
Your retirement tax bracket is likely higher than current
- Current tax bracket: 22%
- Expected retirement bracket: 35% (if you have large RMDs, pensions, Social Security)
- Converting now at 22% saves 13% of the conversion amount in taxes
You'll have significant Roth income in retirement
- Roth conversions don't trigger Medicare IRMAA premiums (Roth withdrawals don't count as income)
- Conversions don't affect taxation of Social Security
- Roth IRA has no RMDs—you can leave it invested and pass it tax-free to heirs
You expect tax rates to increase
- Current rates (extended by OBBBA to 2025) may revert to higher rates (28%+) after 2025
- Converting now locks in 22-24% rates
You have access to the "backdoor Roth"
- If you earn too much to directly contribute to Roth, you can contribute to traditional IRA and convert
- This lets high earners build Roth accounts (subject to pro-rata rules)
Roth Conversions Don't Make Sense If:
You're still in peak earning years (highest tax bracket)
- Current bracket: 35-37%
- Converting now locks you into paying the highest rate
- Better to wait for lower income years (early retirement, etc.)
Your retirement income will be lower
- You'll collect Social Security but have no other income
- Your retirement tax bracket may be 12% or lower
- Converting now at 24% costs more than paying 12% at retirement
You need the money now
- Conversion isn't free—you must pay income tax
- If you have to use IRA funds to pay the tax (not ideal), you lose those funds to taxes
- Only convert if you can pay taxes from other savings
You have high current income
- Conversion adds to your AGI, potentially triggering IRMAA Medicare premiums
- Conversion may push you into higher brackets
- The tax cost today is substantial
Filling the Lower Tax Brackets: The Core Conversion Strategy
The smartest Roth conversion strategy is to "fill the lower brackets" during low-income years:
Example: Filling 2026 Brackets
Scenario: You're 62, semi-retired with low income, and have a $1 million traditional IRA
Your 2026 Income:
- Self-employment income from small consulting: $50,000
- Social Security: $0 (not claiming yet)
- Investment income: $5,000
- Total: $55,000
- Standard deduction: $15,000
- Taxable income: $40,000
Tax Brackets for Single Filer (2026):
- 10%: $0 - $11,550 (used: $11,550)
- 12%: $11,551 - $47,150 (used: $28,599 of $35,599 available)
Conversion Strategy: You can convert up to $28,599 (to fill the 12% bracket completely) and pay only 12% tax:
- Convert: $28,599
- Tax cost: $28,599 × 0.12 = $3,432
If you didn't convert and let that money grow in traditional account:
- At retirement (age 75): $28,599 grows to ~$100,000 (at 6% over 13 years)
- Tax at retirement in 24% bracket: $24,000
- Tax savings from converting now: $24,000 - $3,432 = $20,568
This is the power of filling lower brackets during low-income years.
The IRMAA (Medicare Premium) Trap
There's one major complication: Roth conversions increase your Modified Adjusted Gross Income (MAGI) for 2 years, which determines your Medicare premiums if you're on Medicare:
Example: IRMAA Trap
Scenario: You're 65, on Medicare, planning to convert $50,000 to Roth in 2026
Your 2026 MAGI without conversion: $100,000
- Medicare Part B premium: $185/month (standard)
Your 2026 MAGI with $50,000 conversion: $150,000
- Medicare Part B premium: $370/month (double!)
- Additional cost: $185/month × 12 = $2,220/year
But here's the trap: The premium increase is based on 2024 MAGI. So:
- 2026 conversion affects 2028 premiums (2-year lookback)
- You won't see the IRMAA increase until 2028
Full cost of the conversion:
- Tax paid in 2026 (22% on $50,000): $11,000
- IRMAA increase for 2028-2030 (3 years of $2,220): $6,660
- Total: $17,660 for $50,000 conversion
This is less favorable than the 22% tax rate suggests. For those on Medicare, factor in the IRMAA impact 2 years later.
Multi-Year Conversion Strategy (Ages 60-73)
If you're retiring early (age 60) and won't claim Social Security until 70, you have 10 years of low income. Here's how to structure conversions:
Strategy: Convert $30K-$40K Annually (Ages 60-70)
Scenario:
- Age 60: Retire with minimal income ($30,000/year from part-time work)
- Age 70: Claim Social Security ($40,000/year)
- Age 73: RMDs start
- Traditional IRA: $600,000
Annual Conversions (Age 60-70, Years 1-10):
- Each year, convert $40,000 (to fill the 12% bracket as much as possible)
- Tax on each conversion: ~$4,800 (12% bracket)
- Total conversions over 10 years: $400,000
- Total taxes paid: $48,000
Alternative: No Conversions
- Traditional IRA remains $600,000 (plus growth)
- At age 73, RMDs begin at high income (Social Security + pension + RMDs)
- Your RMD is ~$25,000/year; with Social Security $40,000, total income is $65,000
- Taxable income in 22% bracket; taxes on RMD alone: $5,500/year
- Over 20 years of RMDs (to age 93): $110,000+ in taxes
Comparison:
- Conversion strategy: $48,000 in taxes over 10 years (early retirement window)
- No conversion: $110,000+ in taxes over 20 years (during RMDs and later life)
- Savings: $62,000+ over lifetime
Plus: The converted Roth grows tax-free and can be passed to heirs tax-free.
The 5-Year Roth Rule
One important limitation: You must follow the 5-year rule to withdraw Roth contributions without penalty
The Rule
Each Roth account has its own 5-year clock:
- Year you open the Roth: Year 1
- You can withdraw contributions (not earnings) anytime
- You can withdraw earnings penalty-free AFTER age 59.5 AND 5-year clock expires
Example:
- 2026: Convert $50,000 to Roth at age 60
- 2026-2030: This is your 5-year clock (years 1-5)
- 2031 (year 6): You can withdraw the $50,000 penalty-free
- But earnings on the $50,000 still require age 59.5+ AND 5-year clock
This isn't a major limitation if you're over 59.5 (most early retirees are), but it's worth knowing.
The Pro-Rata Rule Complication
There's a major tax trap many people miss: the pro-rata rule
The Rule
If you have BOTH traditional and Roth IRAs, conversions are taxed on a pro-rata basis:
Example: The Trap
- Traditional IRA: $900,000 (pre-tax)
- Roth IRA: $100,000 (after-tax)
- Total: $1,000,000
You want to convert $100,000 (a small portion) to Roth, thinking it's all after-tax and tax-free:
But the IRS says: "You have 10% after-tax ($100K of $1M) and 90% pre-tax ($900K of $1M). Your conversion must come from the same proportion."
- Your $100,000 conversion consists of:
- $90,000 from pre-tax portion (taxable!)
- $10,000 from after-tax portion (tax-free)
- Taxes owed on conversion: 90% × $100,000 = $90,000
This is a major complication for those with large traditional IRA balances and small Roth balances.
Workaround: Rollover Traditional to 401(k)
If your employer offers a 401(k) rollover, you can move traditional IRA funds INTO the 401(k), removing them from the pro-rata calculation:
- Roll $900,000 of traditional IRA into 401(k)
- Leave $100,000 of after-tax in traditional IRA
- Convert $100,000 (now it's all after-tax) to Roth
- Tax on conversion: 0%
This is a sophisticated strategy but highly valuable if you have large traditional IRAs and small Roth balances.
Action Steps: Implement a 2026 Roth Conversion
Step 1: Calculate Your 2026 Income
Determine your total 2026 income from all sources:
- W-2 wages
- Self-employment income
- Pension / Social Security (if claiming)
- Investment income
- Rental income
- Withdrawals from savings
Target: Lower income years where you can afford to pay conversion taxes without withdrawing from retirement accounts.
Step 2: Determine Your Tax Bracket
Using 2026 tax brackets, calculate where your income ends. Identify the room remaining in your current bracket(s).
Example: If taxable income is $40,000 and you're single, you have ~$28,599 remaining room in the 12% bracket before entering the 22% bracket.
Step 3: Account for IRMAA (If On Medicare)
If age 65+ and on Medicare, factor in the IRMAA impact 2 years later. Conversions are less attractive if they trigger Medicare premium increases.
Step 4: Decide Conversion Amount
Convert enough to fill your lower brackets without jumping into the next bracket (unless you intentionally want to):
- If you have $28,599 room in 12% bracket: Convert up to $28,599
- If you want to fill into the 22% bracket: Convert up to $35,599 (12% + 22% room)
Step 5: Execute the Conversion
- Contact your IRA custodian (Fidelity, Schwab, Vanguard, etc.)
- Request a direct transfer from traditional IRA to Roth IRA
- Important: Use direct transfer, not "indirect rollover" (IRS has strict rules on indirect rollovers)
- Custodian will issue Form 1099-R showing the conversion
Step 6: File Tax Return and Pay Tax
- On your 2026 tax return (filed April 2027), report the conversion
- Form 8606 (Pro-Rata IRA Contribution/Distribution) required
- Pay income tax on the conversion amount (have estimated tax withholding or pay with return)
Step 7: Plan for Following Years
- If 2027 also has lower income, repeat the conversion
- Build a multi-year conversion ladder filling lower brackets each year
Key Takeaways
Roth conversions allow you to pay tax now at known rates (22-24% in 2026) to avoid potentially higher rates later
Low-income years (early retirement, career breaks) are ideal for conversions because you fill lower tax brackets
OBBBA's extension of current tax rates makes 2026 an attractive conversion window—rates may increase after 2025
The IRMAA trap means Medicare beneficiaries should factor in premium increases 2 years later when calculating conversion costs
Multi-year conversions during low-income years (60-73) can save $50,000+ in lifetime taxes
The pro-rata rule requires careful planning if you have both traditional and Roth IRAs—consider rolling traditional to 401(k) as a workaround
Conversions are only beneficial if you can pay taxes from non-IRA funds—don't convert if you'd have to withdraw from the account to pay the tax
If you're between ages 60-70, semi-retired, or in a low-income year, work with a CPA to model your 2026 Roth conversion opportunity. The current tax rates won't last forever.