Roth conversions are often marketed as an obvious way to “save taxes.” They are not. A conversion voluntarily accelerates taxable income. It can be valuable when today’s tax cost is favorable compared with the taxes and restrictions the household may face later—but the result depends on assumptions that should be tested.

What a Roth conversion actually does

A conversion moves money from a traditional retirement account into a Roth account. The converted amount is generally taxable in that year. In exchange, qualified Roth IRA withdrawals may be tax-free, and the original Roth IRA owner is not required to take lifetime RMDs.

The conversion itself does not create wealth. It changes when taxes are paid, which account pays them, and how future withdrawals may be treated.

Five questions to answer before converting

1. Is today’s marginal tax rate likely to be favorable?

Compare the tax on the next converted dollar with the rate that dollar might face if withdrawn later. Future tax law is unknowable, so useful planning compares several scenarios instead of pretending one forecast is certain.

2. How large could future RMDs become?

A large tax-deferred balance can eventually create mandatory taxable income. Conversions may reduce that balance, but paying a high rate today merely to avoid a lower rate later would not improve the result.

3. Where will the conversion tax come from?

Paying the tax from cash or a taxable account may preserve more assets inside the Roth, but it also reduces liquidity. Withholding taxes from the converted retirement money leaves less invested and can create additional complications for people below age 59½.

4. How long can the Roth remain invested?

The longer the time horizon, the more opportunity the Roth account may have to compound. A conversion is less compelling when the money will be withdrawn soon or the tax cost consumes resources needed for near-term spending.

5. Who is expected to use the account?

A couple converting for their own future flexibility may reach a different conclusion from one primarily planning for beneficiaries. The beneficiaries’ likely tax circumstances and distribution rules belong in the analysis.

“Fill the bracket” is not a complete strategy. Tax brackets are important, but conversion income can interact with deductions, credits, investment gains, Social Security taxation and other income-based thresholds.

Three conversion approaches worth comparing

No conversion

This may be appropriate when the current tax rate is already high, liquidity is limited, the money will be needed soon or future taxable income appears manageable.

Measured annual conversions

Converting a calculated amount each year can provide control and allow the plan to respond to tax changes, portfolio values and household needs. The amount should be recalculated before each transaction.

A larger conversion during an unusual opportunity

A market decline, business loss or temporary income reduction may lower the cost of converting. A larger conversion can still be a mistake if it exceeds the household’s desired marginal rate or drains needed cash.

The practical takeaway

A Roth conversion should solve a projected problem, not follow a slogan. The decision is strongest when it is based on a multi-year tax projection, a retirement-income plan and a clear explanation of which assumptions could change the recommendation.

Separate the conversion amount from its tax cost

If a hypothetical $40,000 fully taxable conversion falls entirely within a 22% federal marginal bracket, its federal tax cost is $8,800 before other tax interactions. State tax, lost deductions or credits, and changes in income-based premiums could add to that cost. A blended or effective tax rate from last year’s return will not necessarily measure the cost of the next converted dollar.

Compare three projections using the same spending, investment-return and longevity assumptions: no conversion, a smaller annual conversion and a larger one. Include the cash spent on taxes in every comparison. A strategy should be judged on after-tax resources and flexibility, not the size of the Roth account alone.

Check the account rules before moving money

After-tax IRA basis can change the taxable portion; the pro-rata calculation generally considers the owner’s traditional, SEP and SIMPLE IRAs together. Required distributions cannot be converted. Qualified Roth withdrawals also have holding-period requirements, and early withdrawals of converted amounts can involve a separate five-year rule. IRS Publication 590-B explains these distribution rules.

Important information: Roth conversions can create substantial tax consequences and are not suitable for everyone. This article is educational and is not individualized tax advice. Review any conversion with a qualified tax professional. Official references: IRS Roth IRA guidance and IRS RMD guidance.

Evaluate the conversion within your full retirement plan.

The Impact Retirement Plan™ can compare Roth conversions with future income, withdrawals, taxes and legacy priorities.

Take the 2-Minute Retirement Checkup Prefer a conversation? Schedule with Brian →