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A Roth IRA conversion can be one of the most powerful moves in your retirement toolkit — but it is not right for everyone. Done at the right time, it saves tens of thousands in future taxes. Done carelessly, it triggers a massive and unnecessary tax bill.
A Roth IRA conversion is the process of moving money from a pre-tax retirement account — a Traditional IRA, SEP IRA, or Traditional 401(k) — into a Roth IRA. You pay income tax on the converted amount now. In return, all future growth and qualified withdrawals are completely tax-free. There is no income limit on conversions, and there is no cap on how much you can convert in a given year.
- The converted amount is added to your ordinary income for the tax year. On a $75,000 salary plus $25,000 conversion, the IRS treats your taxable income as $100,000. The tax owed on the $25,000 at the 22% bracket is roughly $5,500 — the “price of admission” for tax-free growth and withdrawals for life. Pay this tax from outside funds, not from the conversion itself.
- The bracket-filling strategy is the most tax-efficient approach: convert only enough each year to fill your current bracket without spilling into the next one. Spreading a $125,000 conversion over 5 years at 22% costs $27,500 in taxes. Converting it all at once pushes into the 32% bracket and costs $35,000 or more.
- The pro-rata rule prevents you from cherry-picking which IRA dollars to convert. If you have both pre-tax and after-tax money across all Traditional IRAs, every conversion is treated as a proportional mix of both. With $90,000 pre-tax and $10,000 after-tax across all IRAs, a $10,000 conversion is 90% taxable ($9,000) regardless of which account you pull from.
- Early retirement (between leaving work and taking Social Security) is often the golden window for conversions. With little or no earned income, large conversions can be taxed at 10 to 12% — rates that may be far lower than the bracket you occupied while working. FIRE practitioners often build their entire retirement tax strategy around aggressive conversions during this period.
- Roth IRAs have no Required Minimum Distributions during the owner’s lifetime. Converting reduces future RMD burden, which keeps you in a lower tax bracket in retirement, reduces the portion of Social Security that gets taxed, and preserves more of the account for beneficiaries.
Conversion vs backdoor Roth: the difference
| Feature | Roth conversion | Backdoor Roth IRA |
|---|---|---|
| What it does | Moves existing pre-tax IRA/401(k) money to Roth | Contributes new after-tax money to Roth via a Traditional IRA |
| Amount | No annual limit | Limited to $7,000/year ($8,000 if 50+) |
| Tax impact | Tax on full converted (pre-tax) amount | Minimal if no pre-tax IRA balances exist (pro-rata rule) |
| Best for | People with existing pre-tax retirement funds | High earners who exceed Roth IRA income limits |
A Roth conversion deals with money already in a pre-tax account. The backdoor Roth IRA is a contribution strategy for high earners who cannot contribute directly to a Roth. They solve different problems and can work together.
Traditional vs Roth: compare your long-term options
Roth vs Traditional IRA Calculator
How much should you convert this year?
Bracket-Filling Conversion Calculator
See how much you can convert this year while staying in your current bracket, and what it will cost.
The tax math: what you actually owe
When you convert pre-tax dollars to a Roth IRA, the converted amount is added to your ordinary income for that tax year. On a $75,000 salary plus $25,000 conversion, taxable income becomes approximately $100,000 (before deductions). The $25,000 is taxed at your marginal rate.
Critical rule: Pay the tax bill from non-retirement funds — a savings account or taxable brokerage account. Paying taxes from the conversion itself has two problems: (1) it reduces the amount growing tax-free inside the Roth, and (2) if you are under 59.5, the withheld portion may be treated as an early distribution subject to the 10% penalty.
Who benefits most from a Roth conversion
You are in a low-income year. Between jobs, on sabbatical, or in a year where business income is lower than usual. Lower income means lower brackets, which means a lower conversion tax rate.
You expect higher taxes in the future. If you are early in your career with income expected to rise significantly — or if you believe Congress will raise tax rates broadly — converting now locks in today’s lower rate on those dollars permanently.
You have a long time horizon. Converting $50,000 at age 30 that grows to $400,000 by age 65 means $350,000 in growth you will never pay taxes on. The younger you are, the more compounding years that tax-free status covers.
You want to reduce future RMDs. Traditional IRAs require Required Minimum Distributions starting at age 73. Roth IRAs have no RMDs during the owner’s lifetime. Converting reduces future RMD burden, which keeps you in lower retirement brackets and reduces the taxable portion of Social Security benefits.
You want to leave a tax-free inheritance. Inherited Roth IRAs are income-tax-free for beneficiaries (though they must be distributed within 10 years under the SECURE Act). Roth money is the cleanest asset to pass on.
Market downturns are conversion opportunities. If your Traditional IRA drops from $100,000 to $70,000 during a market dip, converting at $70,000 means you pay tax on $70,000 instead of $100,000 — and all the recovery growth happens inside the Roth, tax-free.
Who should think twice
You are in peak earning years and converting would push income into the 32% or 37% bracket. If you expect to be in a lower bracket in retirement, converting at today’s high rate costs more than it saves.
You do not have cash outside retirement accounts to pay the tax bill. Pulling tax dollars from the conversion defeats much of the purpose.
You are close to retirement and need the money soon. Each conversion has a 5-year holding period before the converted principal can be withdrawn without penalty (if you are under 59.5).
The pro-rata rule: the hidden tax trap
The pro-rata rule says you cannot cherry-pick which dollars to convert. If you have both pre-tax and after-tax (non-deductible) money across all Traditional IRAs, every conversion is treated as a proportional mix of both — regardless of which specific account you pull from.
Example: Traditional IRA A: $90,000 pre-tax. Traditional IRA B: $10,000 after-tax. Total: $100,000. After-tax percentage: 10%.
Converting $10,000 does not let you claim you are converting only the after-tax money. The IRS says 90% ($9,000) is taxable and only 10% ($1,000) is tax-free. This is reported on IRS Form 8606, which looks at all Traditional, SEP, and SIMPLE IRA balances combined.
How to avoid the pro-rata rule: Roll your pre-tax IRA money into your current employer’s 401(k) if the plan accepts incoming rollovers. This leaves only after-tax money in the Traditional IRA, making conversions essentially tax-free. Verify that your 401(k) plan accepts reverse rollovers before building your conversion strategy around this.
The two 5-year rules
5-year rule 1 — the earnings rule: Your Roth IRA must be open for at least 5 tax years before you can withdraw earnings tax-free and penalty-free. This clock starts January 1 of the year you first contributed to or converted into any Roth IRA. It only needs to be satisfied once in your lifetime. If you opened a Roth IRA in 2020, the 5-year clock has already passed.
5-year rule 2 — the conversion-specific rule: Each conversion has its own separate 5-year holding period. If you are under 59.5, you must wait 5 years from the conversion year before withdrawing that converted principal without the 10% early withdrawal penalty. This rule does not apply once you are past 59.5 — after that age, there is no early withdrawal penalty regardless.
Practical impact: Convert $50,000 in 2026 and you can withdraw that principal (not earnings) penalty-free starting January 1, 2031, even if you are under 59.5. For most people doing long-term retirement conversions, these rules rarely matter because they will not touch the money for decades.
Step-by-step: how to execute a conversion
- Check your current tax situation. Know your taxable income and marginal bracket. Determine how much room you have before hitting the next bracket. Use the calculator above for the specific numbers.
- Decide how much to convert. The bracket-filling method: convert just enough to fill your current bracket without spilling into the next. Many people convert a fixed amount annually rather than everything at once.
- Open a Roth IRA if you do not have one. Fidelity, Schwab, and Vanguard all offer free accounts. If you already have a Roth IRA, your 5-year clock may already be running — a bonus.
- Contact your brokerage. Most major brokerages allow online conversions in minutes. Converting from a 401(k): roll to a Traditional IRA first (unless your plan allows in-plan Roth conversions), then convert to Roth.
- Invest the converted funds immediately. Money landing in a Roth sits in a money market until you invest it. Choose your allocation and invest right away — do not let cash sit uninvested.
- Set aside money for taxes. No taxes are withheld automatically on a conversion. You will owe income tax when you file. For large conversions, make a quarterly estimated tax payment to avoid underpayment penalties.
- File Form 8606. Your brokerage sends a 1099-R documenting the conversion. Report it on Form 8606 with your tax return.
The multi-year bracket-filling strategy
The real power of Roth conversions is in spreading them across years to stay in favorable brackets. Here is how a 5-year partial conversion of $125,000 compares to a single-year conversion:
| Year | Amount converted | Tax bracket | Estimated tax |
|---|---|---|---|
| Year 1 | $25,000 | 22% | ~$5,500 |
| Year 2 | $25,000 | 22% | ~$5,500 |
| Year 3 | $25,000 | 22% | ~$5,500 |
| Year 4 | $25,000 | 22% | ~$5,500 |
| Year 5 | $25,000 | 22% | ~$5,500 |
| Total (5-year) | $125,000 | 22% | ~$27,500 |
Converting the full $125,000 in a single year at the same $70,000 income level pushes a large portion into the 32% bracket. Total tax: roughly $35,000 or more. The patient 5-year approach saves approximately $7,500 in taxes on the same conversion amount.
Frequently Asked Questions
Is there an income limit on Roth IRA conversions?
No. Anyone can do a Roth IRA conversion regardless of income. The income limits that apply to Roth IRA direct contributions ($150,000 single / $236,000 married filing jointly in 2026, where the phase-out begins) do not apply to conversions. This is why the backdoor Roth IRA strategy — contributing to a Traditional IRA then converting — works for high earners: the conversion step has no income restriction. You can convert $1 or $1,000,000 in a single year with no income test.
Can I undo a Roth conversion?
No, not under current tax law. The Tax Cuts and Jobs Act of 2017 eliminated “recharacterization” of Roth conversions — the ability to reverse a conversion and put the money back in the Traditional IRA. Prior to 2018, you could undo a conversion if the account value dropped after conversion. That option no longer exists. This makes timing more important: converting during a market downturn (when valuations are lower) is strategically advantageous, and you need to be confident in your decision before executing.
How do Roth conversions affect Medicare premiums (IRMAA)?
This is an important consideration for people 63 and older or approaching Medicare eligibility. Medicare Part B and D premiums are income-based through a system called IRMAA (Income-Related Monthly Adjustment Amount). High conversion amounts in a single year can push your Modified Adjusted Gross Income above IRMAA thresholds, triggering premium surcharges for Medicare that apply two years later. For example, a large 2026 conversion could increase 2028 Medicare premiums significantly. IRMAA surcharges start at $206,000 for single filers and $412,000 for married filers. If you are in or near Medicare, model the IRMAA impact before executing large conversions — staying just below a threshold can save thousands per year in premiums.
Should I convert if I am in the 22% bracket?
Often yes, particularly if you are under 50. The 22% rate is historically moderate — you are paying a known tax rate today in exchange for tax-free growth that could span 30+ years. The bet: that future withdrawals (from Social Security income, RMDs, and other sources stacking on top of each other in retirement) would put you in a bracket at or above 22% anyway. Converting at 22% now avoids that uncertainty. If you are confident your retirement income will be very low (well below $50,000/year in today’s dollars), you might be better off keeping the money in Traditional accounts and paying 12% or less on withdrawals. Use the bracket-filling calculator above to see your specific numbers and compare.
What happens to my Roth conversion if I die before withdrawing it?
Your heirs inherit the Roth IRA income-tax-free. Under the SECURE Act, most non-spouse beneficiaries must distribute inherited Roth IRA funds within 10 years, but those distributions remain tax-free (since you already paid tax at conversion). This is one of the most compelling estate planning arguments for Roth conversions: Traditional IRA money left to heirs is taxed as ordinary income when withdrawn, potentially at the heir’s peak-earning bracket. Roth IRA money passes completely income-tax-free. If leaving assets to children or other beneficiaries matters to you, Roth is the cleanest inheritance structure available in a retirement account.
Does converting a SEP IRA or SIMPLE IRA to a Roth IRA work the same way?
Yes. SEP IRA and SIMPLE IRA balances (both pre-tax accounts) can be converted to a Roth IRA using the same process and same tax treatment. The converted amount is added to ordinary income in the year of conversion. The pro-rata rule applies and looks at all Traditional, SEP, and SIMPLE IRA balances combined — not just the specific account being converted. SIMPLE IRAs have an additional restriction: they cannot be converted within the first 2 years of establishing the SIMPLE IRA. After 2 years, conversions proceed normally. SEP IRAs have no such waiting period.
What is the best year to do a Roth conversion?
The ideal conversion year has one or more of these characteristics: lower-than-normal income (job gap, career transition, early retirement, business loss year), room remaining in a low bracket before it ends (the 12% bracket ending at $48,475 for single filers in 2026), no large other income events (large capital gain realization, big bonus) competing for bracket space, and ability to pay the tax bill from outside funds without stress. Market downturns add an additional bonus: the same number of shares converted at lower prices means lower taxable income. The worst years to convert are peak-earning years when salary plus bonus plus conversion would all compete for the same high brackets simultaneously.
How do I know if a Roth conversion will save me money long-term?
The core test: if you expect your effective tax rate in retirement to be higher than your current marginal rate on the conversion, converting makes mathematical sense. This is harder to know than it sounds — retirement income includes RMDs from Traditional accounts, Social Security (up to 85% taxable), capital gains, and potentially other sources, all stacking together. A rough framework: if your Traditional IRA balance is large relative to expected retirement spending, RMDs alone may push you into higher brackets than your current rate. A fee-only fiduciary financial planner can model your specific situation with projections across multiple scenarios. The roth_vs_traditional calculator above also provides a useful comparison framework.
The bottom line
The Roth conversion question comes down to one judgment: will your effective tax rate be higher or lower in retirement than it is today on the converted amount? For most working Millennials and Gen Z still early in their careers, converting during lower-income years — a gap year, an early retirement period, a year between jobs — locks in today’s lower rates on money that will compound tax-free for decades.
The bracket-filling calculator above shows your specific maximum conversion amount for this year and the exact tax cost. Start with a small conversion to understand the mechanics, then build a systematic multi-year plan once you are comfortable with the process.
Related reading:
- Considering the backdoor Roth alongside a conversion? Read our backdoor Roth IRA guide — the pro-rata rule explained and how to combine both strategies.
- Planning to retire early and use conversions as income? Read our Roth conversion ladder guide — the complete FIRE strategy with a year-by-year timeline planner.
- Need to move a 401(k) to a Traditional IRA first? Read our 401(k) rollover guide — the direct rollover process that avoids withholding and penalties.
