What Is a Roth Conversion?

Research. Education. Perspective.

A Roth conversion moves eligible retirement money from a traditional or other pre-tax retirement arrangement into Roth status.

The basic tradeoff is simple:

> Recognize income tax on previously untaxed retirement money now in exchange for moving that money into a Roth IRA, where future qualified distributions can be tax-free.

The mechanics become more complicated when an investor has nondeductible IRA basis, multiple traditional IRAs, required minimum distributions, employer-plan money, or plans to withdraw converted funds before age 59½.

Key Takeaways

• A Roth conversion is not the same as a regular Roth IRA contribution.
• Previously untaxed amounts converted to Roth are generally included in gross income for the year of conversion.^[1]
• A conversion can be completed by a 60-day rollover, trustee-to-trustee transfer, or same-trustee transfer.^[1]
• If a traditional IRA contains nondeductible basis, Form 8606 is used to determine taxable and nontaxable amounts.^[3][4]
• For Form 8606 purposes, traditional IRAs generally include traditional SEP and SIMPLE IRAs.^[3]
• An amount that must be distributed as an RMD for the year cannot itself be converted.^[1]
• Roth conversions made after 2017 generally cannot be recharacterized back to a traditional IRA.^[1][5]
• The five-year conversion recapture rule is separate from the five-year rule used to determine whether Roth earnings are part of a qualified distribution.^[2]

What Is a Roth Conversion?

> ROIStreet Definition > > A Roth conversion is a transaction that moves eligible retirement assets from traditional tax treatment into a Roth IRA, generally causing previously untaxed amounts to become taxable income in the year of conversion.

Suppose a traditional IRA contains $40,000 funded entirely with deductible contributions and tax-deferred earnings.

If the owner converts all $40,000 to a Roth IRA, the $40,000 would generally be included in gross income for that year.^[1]

The transaction changes the tax character of the money. It does not create a deduction or erase the tax already embedded in pre-tax retirement assets.

Roth Conversion vs. Roth IRA Contribution

A conversion and a contribution can both add money to a Roth IRA, but they are different transactions.

For 2026, the annual IRA contribution limit is $7,500, plus a $1,100 catch-up amount for an eligible person age 50 or older. Those limits apply to regular IRA contributions, not to the amount of an otherwise eligible Roth conversion.^[1]

Why Can a Conversion Create Taxable Income?

Traditional retirement accounts often contain money that has never been subject to federal income tax.

Examples include:

• deductible traditional IRA contributions
• pre-tax 401(k) rollovers
• pre-tax SEP IRA balances
• pre-tax SIMPLE IRA balances
• tax-deferred earnings

When that money is converted to Roth status, the IRS generally requires previously untaxed amounts to be included in gross income.^[1]

Fully Taxable Conversion Example

Assume:

• Traditional IRA: $60,000
• Nondeductible basis: $0
• Amount converted: $20,000

If the IRA contains only pre-tax money, the $20,000 conversion is generally taxable income.

The remaining $40,000 stays in traditional status.

What Is IRA Basis?

Basis is the portion of a traditional IRA that has already been taxed.

A common source is a nondeductible traditional IRA contribution.

If someone contributes to a traditional IRA and does not deduct that contribution, the nondeductible amount generally creates basis that should be tracked on Form 8606.^[3][4]

Basis matters because already-taxed dollars should not normally be taxed a second time.

The Pro-Rata Rule

A common misconception is that an investor can keep pre-tax IRA money in one account, place after-tax money in another IRA, and convert only the after-tax dollars tax-free.

Form 8606 generally prevents that selective isolation.

For this calculation, the IRS treats traditional IRA balances as an aggregated pool. The Form 8606 instructions state that “traditional IRA” generally includes traditional SEP IRAs and traditional SIMPLE IRAs.^[3]

A simplified conceptual formula is:

after-tax basis ÷ total traditional IRA pool = nontaxable percentage

The actual tax return calculation should be completed using Form 8606 and its instructions.

Pro-Rata Example

Assume:

• Nondeductible basis: $20,000
• Pre-tax traditional/SEP/SIMPLE IRA assets: $80,000
• Total traditional IRA pool: $100,000
• Amount converted: $20,000

Conceptually:

$20,000 ÷ $100,000 = 20% after-tax

A simplified estimate would therefore treat:

• $4,000 of the conversion as nontaxable
• $16,000 as taxable

The investor cannot simply designate the exact $20,000 of basis as the money being converted while ignoring the pre-tax balance.

Form 8606 also uses year-end IRA values, which is why other transactions during the year can affect the result.^[3]

Does a 401(k) Count in the IRA Pro-Rata Rule?

A 401(k) is not itself a traditional IRA for the Form 8606 IRA aggregation calculation.

That distinction can matter if an employer plan accepts roll-ins from a traditional IRA.

But moving assets into an employer plan merely to change a tax calculation can affect investment choices, fees, creditor protection and access. It should be evaluated as a broader retirement-plan decision.

What Is a Backdoor Roth IRA?

A backdoor Roth is not a special account.

It generally describes:

1. making a nondeductible contribution to a traditional IRA, then
2. converting some or all of that IRA to Roth.

The pro-rata rule is critical. Existing pre-tax traditional, SEP or SIMPLE IRA balances can make the conversion partly or mostly taxable.

Does a Roth Conversion Have an Income Limit?

Roth conversion eligibility is distinct from the modified-AGI limits that restrict regular Roth IRA contributions.

Income restrictions on Roth conversions were removed beginning in 2010.

Income still matters because a taxable conversion itself increases gross income and can affect other tax calculations.

How a Conversion Can Affect the Rest of a Tax Return

A taxable conversion can affect:

• marginal federal income-tax brackets
• taxation of Social Security benefits
• Medicare income-related premium adjustments in later years
• deductions and credits tied to income
• net investment income tax exposure
• state income taxes
• health-insurance subsidy calculations

The economic effect can therefore be larger than simply:

conversion amount × tax rate

Partial Roth Conversions

A conversion does not have to involve an entire traditional IRA.

IRS Publication 590-A allows all or part of a traditional IRA to be converted.^[1]

Suppose an investor has a $300,000 traditional IRA but wants to convert only $30,000.

The investor can convert $30,000 and leave the remaining $270,000 in traditional status.

If the account is entirely pre-tax, the converted $30,000 would generally be included in income.

If basis exists, the Form 8606 pro-rata calculation becomes relevant.

Why Partial Conversions Are Often Analyzed

A partial conversion can spread taxable income across more than one year.

For example, an investor might compare:

• converting $100,000 in one year

with:

• converting $25,000 per year over four years

The future is uncertain, however. Tax brackets, income, investment returns and tax law can all change.

A smaller conversion is not automatically better, and a larger conversion is not automatically better.

The useful comparison is the current tax cost versus the expected long-term tax treatment.

Three Ways to Convert a Traditional IRA

IRS Publication 590-A describes three conversion methods.^[1]

Trustee-to-trustee transfer

The trustee of the traditional IRA sends the assets directly to the trustee of the Roth IRA.

Same-trustee transfer

The institution that holds the traditional IRA transfers or redesignates the assets into a Roth IRA at the same institution.

60-day rollover

The investor receives a distribution and contributes the amount to a Roth IRA within the applicable 60-day period.

A direct transfer can reduce the operational risk of personally handling rollover funds and missing the deadline.

Converting Employer-Plan Money

Eligible distributions from certain employer retirement plans can also be rolled to a Roth IRA.

Publication 590-A includes eligible rollovers from plans such as:

• 401(k) plans
• pension, profit-sharing and stock bonus plans
• 403(b) plans
• governmental 457 plans^[1]

Previously untaxed amounts rolled to the Roth IRA are generally included in income.^[1]

A direct rollover from an employer plan generally avoids the mandatory withholding that can apply when an eligible distribution is paid directly to the participant.^[1]

What Happens If Taxes Are Withheld?

Suppose an investor requests a $50,000 distribution but $10,000 is withheld for taxes and only $40,000 reaches the Roth IRA.

Unless the investor replaces the withheld amount under the applicable rollover rules, only $40,000 reaches Roth status.

The withheld portion can be treated as a distribution.

For someone under age 59½, that unconverted distributed amount can potentially create an additional-tax issue unless an exception applies.

That is why the source of money used to pay the conversion tax matters.

Does the 10% Additional Tax Apply to the Conversion?

A properly completed conversion itself is generally not subject to the 10% additional tax merely because the investor is under age 59½.^[1]

However, withdrawing taxable converted amounts from the Roth IRA too soon can create a separate issue.

That is where the conversion five-year rule becomes important.

There Is More Than One Roth Five-Year Rule

This distinction is central to Roth IRA taxation.

Five-year rule #1: Qualified Roth IRA distributions

To receive Roth IRA earnings as part of a qualified distribution, the general qualified-distribution rules include a five-tax-year requirement plus a qualifying event such as reaching age 59½, disability, death, or an eligible first-home distribution subject to the statutory rules.^[2]

This clock generally starts with the first tax year for which the owner made a contribution to any Roth IRA.

Five-year rule #2: Conversion recapture

Each conversion can also have its own separate five-tax-year period for determining whether a later distribution of taxable converted amounts can trigger the 10% additional tax.^[2]

IRS Publication 590-B specifically states that the conversion five-year period is separately determined for each conversion and is not necessarily the same as the qualified-distribution five-year period.^[2]

Conversion Five-Year Example

Assume a calendar-year taxpayer makes a taxable Roth conversion in 2026.

The five-year conversion period begins:

January 1, 2026

It is measured by tax years, not by counting exactly five years from the transaction date.

If the investor later withdraws taxable converted amounts during the applicable period while under age 59½, the 10% additional tax can apply unless an exception is available.^[2]

Roth IRA Distribution Ordering Rules

For a nonqualified Roth IRA distribution, IRS Publication 590-B generally applies the following order:^[2]

1. regular Roth IRA contributions 2. conversion and rollover contributions, first-in, first-out - taxable portion first - nontaxable portion second 3. earnings

That order matters because each layer can have different tax consequences.

Why Conversion Timing Matters

A conversion changes taxable income in the year it occurs.

Potential variables include:

• current taxable income
• expected future income
• current and expected future tax rates
• market value at conversion
• years until expected withdrawal
• RMD exposure
• estate-planning objectives
• state tax treatment
• cash available to pay conversion tax

None of those factors guarantees that a conversion will improve after-tax wealth.

Market Decline After a Conversion

Assume an investor converts $100,000 and recognizes income based on that amount.

Several months later, the Roth IRA is worth $75,000.

Current law generally does not allow the investor to recharacterize the conversion back to a traditional IRA simply because the investment declined.

Conversions made after 2017 generally cannot be recharacterized.^[1][5]

The tax event is based on the conversion, not on what the investment is worth later.

Can a Roth Conversion Be Undone?

Generally, no.

Traditional-to-Roth conversions made in tax years beginning after December 31, 2017 cannot be recharacterized back to traditional IRA status.^[1][5]

That is different from recharacterizing certain regular IRA contributions, which remains a separate concept.

Required Minimum Distributions and Roth Conversions

An amount that must be taken as a required minimum distribution for the year cannot itself be converted to a Roth IRA.^[1]

Suppose an IRA owner must take a $20,000 RMD and also wants to convert $50,000.

The required distribution must be handled separately.

The owner cannot label that required $20,000 as part of the Roth conversion.

After satisfying the RMD requirement, other eligible assets can potentially be converted.

Why Roth Conversions Are Discussed Around RMDs

Traditional IRA balances can generate future required minimum distributions.

Roth IRA owners generally do not have lifetime RMDs from their own Roth IRAs.

A conversion can reduce the amount remaining in traditional IRA status and can therefore affect future RMD amounts.

But that benefit comes with current tax recognition.

The decision is a tax-timing tradeoff, not a free tax reduction.

Roth Conversions and Inherited IRAs

Inherited retirement accounts have separate beneficiary rules.

A nonspouse beneficiary generally cannot treat an inherited traditional IRA as the beneficiary's own IRA and simply convert it into the beneficiary's own Roth IRA.

Spousal beneficiaries can have additional options.

Inherited-IRA transactions should therefore not be assumed to follow the same mechanics as an owner's ordinary IRA conversion.

How Roth Conversions Are Reported

Roth conversions are reportable tax transactions.

Form 8606 is used to report conversions from traditional, SEP or SIMPLE IRAs to Roth IRAs and to calculate the tax treatment when basis exists.^[3][4]

The custodian generally reports the distribution on Form 1099-R.

IRS instructions for Forms 1099-R and 5498 state that a traditional IRA distribution known to be converted to a Roth IRA is reported even when the conversion is trustee-to-trustee or completed with the same trustee.^[7]

Form 8606: What It Is Doing Conceptually

When basis exists, Form 8606 generally works through questions such as:

1. How much nondeductible basis existed?
2. Were additional nondeductible contributions made?
3. What distributions occurred?
4. How much was converted?
5. What was the year-end value of the traditional IRA pool?
6. What portion is nontaxable?
7. How much basis remains for future years?

The form is designed to prevent already-taxed basis from being taxed again while also preventing investors from selectively isolating basis when pre-tax IRA money remains in the aggregate pool.

Roth Conversion vs. Recharacterization

These are different concepts.

Conversion

Traditional retirement money moves into Roth status.

Recharacterization

A qualifying IRA contribution is treated as though it had originally been made to a different IRA type.

Current law generally does not permit a completed Roth conversion to be recharacterized back.^[1][5]

Roth Conversion vs. Rollover

A conversion is a rollover transaction that changes tax character.

A traditional IRA-to-traditional IRA rollover generally preserves traditional tax treatment.

A traditional IRA-to-Roth IRA conversion changes the tax treatment.

That change is why previously untaxed amounts generally become current taxable income.

What a Roth Conversion Does Not Do

A Roth conversion does not:

• guarantee lower lifetime taxes
• guarantee tax-free access immediately
• erase tax already embedded in pre-tax retirement money
• bypass the pro-rata rule
• allow an RMD itself to be converted
• guarantee future tax rates will be higher
• eliminate investment risk
• create a tax deduction
• automatically improve estate outcomes

Situations Where a Conversion Is Often Analyzed

A Roth conversion may receive more attention when:

• current taxable income is temporarily lower
• an investor has retired but RMDs have not started
• pre-tax retirement balances are large
• the investor expects higher future tax rates
• there is a long time before expected withdrawals
• estate planning favors Roth assets
• asset values have declined
• the investor is considering a backdoor Roth process

These are reasons to analyze the transaction, not reasons that make it automatically appropriate.

Factors That Can Make a Conversion Less Attractive

Potential drawbacks include:

• a large immediate tax bill
• moving income into a higher marginal bracket
• affecting Medicare premiums or tax credits
• insufficient outside cash to pay the tax
• a short time horizon
• expected lower future tax rates
• state-tax differences
• near-term need for converted funds

Worked Example: Partial Conversion

Assume an investor estimates that an additional $30,000 of taxable income can be recognized before entering a materially higher marginal bracket.

The investor has a $250,000 pre-tax traditional IRA.

One possible transaction is a $30,000 conversion rather than converting the entire IRA.

That would leave roughly:

• $220,000 in traditional status
• $30,000 in Roth status

before market changes and taxes.

The example does not establish that $30,000 is optimal. It illustrates why conversions are often analyzed incrementally.

Worked Example: Basis and Pre-Tax Money

Assume:

• nondeductible IRA basis: $15,000
• pre-tax traditional IRA assets: $85,000
• total traditional IRA pool: $100,000
• Roth conversion: $10,000

Conceptually:

$15,000 ÷ $100,000 = 15% after-tax

A simplified estimate would treat:

• $1,500 as nontaxable
• $8,500 as taxable

Actual reporting should follow Form 8606 because other contributions, distributions, conversions and year-end balances can affect the calculation.

Common Roth Conversion Mistakes

Ignoring the pro-rata rule

The IRA selected for conversion does not necessarily define the tax result.

Forgetting old IRA basis

Nondeductible contributions made years earlier can still matter.

Using conversion proceeds to pay taxes without considering the consequences

Withholding can reduce the amount reaching Roth status and can create distribution consequences.

Assuming every five-year rule is the same

The qualified-distribution clock and individual conversion recapture clocks are separate.

Trying to convert an RMD

Required distributions themselves are not eligible for conversion.^[1]

Assuming the conversion can be reversed

Post-2017 conversions generally cannot be recharacterized.^[1][5]

Looking only at the marginal tax rate

The conversion can affect other income-based calculations.

A Roth Conversion Research Framework

Useful questions include:

1. What type of account holds the money?

Traditional IRA, SEP IRA, SIMPLE IRA, 401(k), 403(b) and 457 plans can have different operational rules.

2. How much of the balance is pre-tax?

This helps estimate taxable income.

3. Is there nondeductible IRA basis?

Review prior Forms 8606.

4. What other traditional, SEP or SIMPLE IRA balances exist?

They can affect the pro-rata calculation.

5. Is an RMD required this year?

The RMD cannot itself be converted.

6. What is the estimated total tax effect?

Look beyond the conversion amount alone.

7. How will the tax be paid?

Using outside cash and withholding from the IRA can have different consequences.

8. How old is the investor?

Age can affect the significance of the conversion five-year recapture rule.

9. When is the money likely to be needed?

Roth distribution treatment depends partly on timing.

10. What future tax assumptions are being made?

The value of conversion depends partly on an uncertain future.

Roth Conversion Decision Tree

Is the money already in Roth status?

If yes → no traditional-to-Roth conversion is needed.

Is an RMD due?

If yes → satisfy the RMD separately before considering conversion of other eligible money.

Does traditional IRA basis exist?

If yes → review Form 8606 and the aggregated IRA pool.

Will the conversion create taxable income?

If yes → estimate federal, state and downstream tax effects.

Will converted funds be needed soon?

If yes → review Roth distribution ordering and the applicable conversion five-year period.

Can the tax be paid without disrupting the retirement plan?

If no → the economics change materially.

This decision tree identifies research questions; it does not produce an individualized recommendation.

Frequently Asked Questions

Is a Roth conversion limited to $7,500 in 2026?

No. The 2026 IRA contribution limit applies to regular IRA contributions. A conversion is a different transaction.

Does a Roth conversion count as income?

The previously untaxed portion generally becomes gross income in the year of conversion.^[1]

Can I convert only the after-tax money in my traditional IRA?

The pro-rata rule generally prevents selectively isolating basis when other pre-tax traditional, SEP or SIMPLE IRA money exists.

Do I pay the 10% early-distribution tax when I convert before age 59½?

A properly completed conversion itself is generally not subject to the 10% additional tax solely because of age.^[1] A later distribution of taxable converted amounts within the separate five-year conversion period can trigger the additional tax unless an exception applies.^[2]

Does every conversion start a new five-year clock?

A separate five-year recapture period generally applies to each conversion.^[2]

Is that the same five-year rule used for Roth earnings?

No. The qualified-distribution five-year rule is separate.^[2]

Can I convert my RMD?

No. An amount required to be distributed for the year cannot be converted.^[1]

Can I reverse a Roth conversion?

Conversions made after 2017 generally cannot be recharacterized back to traditional IRA status.^[1][5]

Do I need Form 8606?

Form 8606 is used to report conversions from traditional, SEP or SIMPLE IRAs to Roth IRAs and is especially important when nondeductible basis exists.^[3][4]

The Bottom Line

A Roth conversion is a tax-character change.

It moves eligible traditional retirement money into Roth status, generally causing previously untaxed amounts to become taxable in the conversion year.

The mechanics become especially important when:

• IRA basis exists
• multiple IRAs are involved
• an RMD is due
• the investor is under age 59½
• converted money may be withdrawn within five years
• the conversion materially changes adjusted gross income

Three concepts prevent many misunderstandings:

1. A conversion is not a regular Roth IRA contribution.
2. The pro-rata rule generally looks across the traditional IRA pool rather than one selected account.
3. There is more than one Roth five-year rule.

A conversion can be useful in some tax situations and expensive in others. Its value depends on the current tax cost, future tax treatment, time horizon and the investor's broader retirement plan.

Sources & References

1. IRS Publication 590-A: Contributions to Individual Retirement Arrangements (IRAs)
2. IRS Publication 590-B: Distributions from Individual Retirement Arrangements (IRAs)
3. IRS: Instructions for Form 8606
4. IRS: About Form 8606, Nondeductible IRAs
5. IRS: Retirement Plans FAQs Regarding IRAs
6. IRS: Rollovers of Retirement Plan and IRA Distributions
7. IRS: Instructions for Forms 1099-R and 5498 (2026)

Educational Disclaimer

ROIStreet publishes educational content intended to help readers better understand retirement accounts, taxation and investing. Nothing in this article should be interpreted as personalized investment, legal, tax or financial advice, or as a recommendation to complete or avoid a Roth conversion. Roth conversion taxation can depend on account history, basis, other retirement accounts, filing status and individual circumstances. Readers should consider qualified tax or financial professionals where appropriate.

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