Optimizing Your Retirement Income with Roth Conversions

Optimizing retirement income with Roth conversions means treating a conversion not as a one-time tax move but as a multi-year cadence that can raise how much you can spend after tax and how long your money can last. The idea is to move pre-tax IRA dollars into a Roth during your lower-income years, pay the tax at today’s rates, and reduce the future taxable income that would otherwise inflate your tax bill, your Medicare premiums, and the tax on your Social Security.

Last reviewed: July 2026 | Written and reviewed by Craig Wear, CFP®, Q3 Advisors

Lowering a single year’s tax bill is only part of the picture. The word “optimizing” points to something larger: your spendable, inflation-adjusted income and the longevity of the portfolio that funds it. This article keeps that income lens throughout, folding in Social Security taxation, Medicare surcharges, the widow’s penalty, and what your heirs inherit, then closes with a self-scoring worksheet you can run on your own numbers. Every figure below carries its tax year and source.

The trough years: your lower-income conversion window

During your working years, wages fill the higher brackets, so converting adds tax at your top marginal rate. Once RMDs start, the required withdrawals themselves push income up. The gap in between is where a conversion often costs the least. If you retire at 62 and delay Social Security to 70, you may have several years of unusually low taxable income, a stretch when converting a slice of your IRA each year can be done at a modest rate. Waiting until 73 can mean converting on top of RMDs, Social Security, and any pension, which stacks the conversion into higher brackets.

Converting to a Roth after age 60 or after you retire is fully allowed. There is no upper age limit and no requirement to have earned income, which separates conversions from Roth contributions.

An income-first framework, not just a tax trick

Think of retirement money in three buckets: taxable brokerage accounts, tax-deferred accounts (traditional IRA and 401(k)), and tax-free Roth accounts. Withdrawals from each are taxed differently. Traditional IRA and 401(k) withdrawals are ordinary income. Brokerage sales generate capital gains. Qualified Roth withdrawals are tax-free.

A common income-first sequence looks like this:

1. Live on taxable brokerage funds early in retirement, realizing capital gains at lower rates and keeping ordinary income low.
2. Use the low-income room those years create to convert part of the traditional IRA to Roth, filling up a target bracket.
3. Draw tax-deferred accounts once RMDs require it, now on a smaller balance because conversions shrank it.
4. Leave Roth dollars to grow and spend last, since they carry no lifetime RMD and pass tax-free to heirs.

The goal is a higher net, after-tax, inflation-adjusted number you can spend each year, not merely a smaller line on one year’s return. A conversion that nudges this year’s tax up can still raise lifetime spendable income if it prevents a much larger tax and premium spike later. You can explore the break-even math behind that trade-off before committing.

How much to convert: filling brackets with the 2026 tables

Start from your projected taxable income for the year, then subtract it from the top of the bracket you are comfortable paying. The difference is your rough conversion ceiling at that rate. Because a conversion is ordinary income, it stacks on top of everything else, so include pensions, interest, dividends, capital gains, and any Social Security already being taxed.

2026 federal income tax brackets, married filing jointly

2026 federal income tax brackets, single filer

Source: Rev. Proc. 2025-32, reproduced by the Tax Foundation, 2026. The 37% top rate was made permanent by the One Big Beautiful Bill Act (P.L. 119-21, signed July 4, 2025). The 2026 standard deduction is $16,100 single and $32,200 MFJ (Source: IRS, Rev. Proc. 2025-32, 2026).

The right ceiling is rarely the same every year. Some planners fill the 12% bracket in the leanest years and stretch into 22% or 24% when a later RMD spike or a survivor’s compressed brackets would otherwise cost more. A structured way to size each year’s number is covered in our guide on how much to convert to a Roth.

How Roth conversions shrink future RMDs

RMDs are the reason many well-funded retirees face rising taxes in their seventies and eighties. A large traditional IRA can generate required withdrawals that push income far above what the household actually spends, dragging Social Security and Medicare along with it. Converting during the trough years reduces the balance that RMDs are calculated on. Roth IRAs carry no RMD during the original owner’s lifetime, and Roth 401(k) accounts have had their lifetime RMDs eliminated since 2024 (Source: SECURE 2.0 Section 325, 2026). You can review the current thresholds on our 2026 required minimum distribution page.

Roth conversions and Medicare IRMAA

The cliff structure matters. Going one dollar over a threshold moves you to the next tier for the whole year, so conversion planning near age 63 and up watches these lines closely. Because of the two-year lookback, a conversion done in 2026 can raise your Medicare premiums in 2028.

2026 Medicare Part B premium by income tier

Source: CMS 2026 Medicare Parts A and B premiums, based on 2024 MAGI. Part D IRMAA surcharges apply separately on the same tiers. Full detail is on our 2026 Medicare IRMAA brackets page.

For a household already on Medicare, sizing a conversion often means stopping just below the next IRMAA cliff, or accepting one higher tier for a single year when the long-run RMD reduction appears to outweigh a one-time premium bump. A conversion done before age 63 does not affect Medicare, since Part B typically starts at 65 and the lookback reaches back two years.

Roth conversions and Social Security taxation

This interaction is one reason the delay-Social-Security-and-convert-early sequence is popular. Years where benefits have not started leave more room to convert without the conversion also taxing your benefits. Once benefits begin, each converted dollar can carry a hidden extra cost as it drags more of your Social Security into taxable territory, an effect sometimes called the tax torpedo. Our page on the taxation of Social Security benefits walks through the provisional-income math.

The mechanics you cannot get wrong

Ordinary income, no caps. A conversion is taxed at ordinary rates on the pre-tax amount converted. There is no dollar limit and no income limit, which is why high earners locked out of Roth contributions can still convert. This also covers a 401(k) or traditional IRA; a 401(k) is generally rolled to a traditional IRA first, or converted in-plan if the plan allows.

Irreversible. The Tax Cuts and Jobs Act permanently eliminated recharacterization of Roth conversions made after 2017 (Source: IRS, 2026). Once done, a conversion cannot be undone, so the year’s amount should be sized before you convert, not after.

The pro-rata rule. If you hold both pre-tax and after-tax (nondeductible) dollars across your traditional, SEP, and SIMPLE IRAs, you cannot convert only the after-tax basis. The taxable share is figured across the combined balance (Source: IRC Section 408(d)(2), Form 8606, 2026). Hypothetical example: a saver with $95,000 pre-tax and $5,000 of after-tax basis, $100,000 total, who converts $10,000 would treat 95% of it, $9,500, as taxable, not zero. Our pro-rata rule guide covers the workaround for isolating basis.

The two five-year rules. One clock governs tax-free treatment of earnings; the other applies to each conversion, running from January 1 of the conversion year. Withdrawing converted principal within five years and before age 59.5 can trigger the 10% early-distribution penalty on the previously taxed amount (Source: IRS Pub 590-B, Topic 557, 2026).

Pay the tax from outside funds. Covering the conversion tax with taxable brokerage money, rather than withholding from the IRA itself, keeps the full converted amount growing tax-free and avoids the 10% penalty that can apply to withheld amounts before 59.5. Using IRA dollars to pay the tax shrinks the very balance you are trying to move.

Reporting. Conversions are reported on Form 8606 with your return, and the custodian issues a Form 1099-R. So yes, a Roth conversion is reported on your taxes even though qualified Roth withdrawals later are not.

A hypothetical multi-year conversion cadence

Consider a hypothetical married couple, both 64, retired, not yet claiming Social Security. Their only taxable income is about $30,000 from brokerage interest and dividends. After the 2026 standard deduction of $32,200 (Source: IRS, 2026), taxable income is near zero, leaving substantial room inside the 12% and 22% brackets.

• They could convert enough to reach the top of the 12% bracket, $100,800 of taxable income for MFJ in 2026, keeping the marginal rate low.
• In a year where a later RMD spike looks likely, they might stretch into the 22% bracket, up to $211,400 of taxable income for MFJ in 2026. Filling that bracket would put MAGI (taxable income plus the $32,200 standard deduction) near $243,600, above the first MFJ IRMAA threshold of $218,000, so once both are on Medicare at 65 they would weigh a one-year premium increase against the long-run RMD reduction.
• They repeat a sized conversion each year from 64 to 72, paying the tax from their brokerage account so the full converted amount stays in the Roth.

By age 73, the traditional IRA is smaller, so RMDs are smaller, Social Security is taxed on a lower base, and the Roth balance can be spent or left to heirs tax-free. The specific amounts depend entirely on the household’s full picture and are not guaranteed outcomes.

The widow’s penalty and why filing status matters

A surviving spouse with a large traditional IRA can face RMDs taxed in single brackets while also crossing IRMAA thresholds that were comfortable as a couple. Converting during the joint-filing years, when the 22% MFJ bracket reaches $211,400 rather than the single ceiling of $105,700 (Source: Rev. Proc. 2025-32, 2026), moves pre-tax money out while the wider brackets are still available.

The 2026 tax picture after OBBBA

The senior deduction carries a quiet catch for conversion planning. Because it phases out at 6 cents per dollar of MAGI above the threshold, income in the phase-out range faces a hidden marginal-rate bump: a conversion dollar there costs its stated bracket rate plus the value of the deduction it erases. For couples with MAGI between $150,000 and $350,000, that can raise the true cost of the next converted dollar. The permanence of the rate schedule also removes the “convert before rates rise” urgency that drove planning when the brackets were set to expire, shifting the focus to your own income curve rather than a legislative deadline.

Leaving a tax-free legacy: the SECURE Act 10-year rule

For households with more than they expect to spend, conversions can shift the tax bill from a high-bracket heir to the retiree’s own lower-bracket trough years. The 2026 federal estate and gift exemption is $15,000,000 per person, made permanent by OBBBA (Source: IRS, Rev. Proc. 2025-32, 2026), so for most families the legacy question is about income tax on inherited dollars rather than estate tax. A Roth balance answers that by arriving tax-free.

Common mistakes to avoid

• Converting too much at once. A single large conversion can push income into the 24%, 32%, or higher brackets and trip IRMAA. Spreading conversions across the trough years usually keeps more of the amount in lower brackets.
• Ignoring IRMAA cliffs. Since the tiers are thresholds, a small overage carries a full-tier premium increase for a year.
• Paying tax from the IRA. This shrinks the balance you are moving and can add a 10% penalty before age 59.5.
• Forgetting the pro-rata rule. Assuming after-tax basis converts tax-free leads to a surprise on Form 8606.
• Converting after RMDs start without a plan. You must take the year’s RMD first; it cannot be converted, and it raises the income the conversion stacks on.

A “how much should I convert this year” worksheet

1. Project taxable income for 2026 before any conversion: pensions, interest, dividends, capital gains, and any taxable Social Security. Subtract the standard deduction ($16,100 single or $32,200 MFJ, 2026).
2. Pick a target bracket ceiling from the 2026 tables above. Subtract your projected taxable income from that ceiling. This is your starting conversion room.
3. Check the IRMAA lines. If you are 63 or older, compare your projected MAGI plus the conversion against the $109,000 single or $218,000 MFJ first threshold and the tier above it. Trim the conversion if it crosses a cliff you are not willing to pay.
4. Check Social Security. If benefits have started, expect part of the conversion to also increase the taxable share of those benefits; reduce your ceiling accordingly, or convert before you claim.
5. Check the senior-deduction phase-out. If you are 65 or older with MAGI in the $75,000 to $175,000 single or $150,000 to $350,000 MFJ range, treat converted dollars there as more expensive because they erode the deduction.
6. Confirm the tax is paid from outside funds. If you would have to use IRA money to pay it, lower the conversion until the outside cash covers the bill.
7. Weigh the survivor and heir angles. If a future single-filer year or a high-bracket heir looms, that argues for filling more of the current bracket now.

The result is a single per-year ceiling that reflects taxes, Medicare, Social Security, the senior deduction, and your legacy goals at once, rather than any one of them alone.

How Q3 Advisors approaches Roth conversion planning

Searchers comparing a financial planner for Roth conversion planning often look for fee structure, fiduciary status, and public disclosures. As a fiduciary registered investment adviser, Q3 Advisors is required to act in clients’ interests, and its background, services, and fee schedule are described in its Form ADV Part 2 brochure, which anyone can read on the SEC IAPD site before deciding to work with the firm. Craig Wear, CFP, founded the firm’s Roth conversion practice around multi-year planning rather than one-off transactions. When evaluating any firm for this work, useful questions include whether the adviser is a fiduciary, how fees are charged (flat fee versus a percentage of assets), whether products are sold, and where to find the Form ADV. This description is factual and is not a testimonial or a claim about results.

Frequently asked questions

At what age should you start doing Roth conversions?

Many households find the useful window opens once wages stop and before RMDs begin at 73, roughly ages 60 to 72 (Source: SECURE 2.0, IRS Pub 590-B, 2026). In these lower-income years, converting can be done at comparatively low rates. There is no minimum or maximum age for a conversion; the right timing depends on your income curve, not a fixed birthday.

How much should I convert to a Roth IRA each year?

A common approach is to convert enough to reach the top of a target bracket, such as the 12% or 22% bracket, without crossing into the next one or tripping an IRMAA cliff. In 2026 the 22% MFJ bracket ends at $211,400 of taxable income (Source: Rev. Proc. 2025-32, 2026). The right figure also weighs Social Security, Medicare, and heirs, as the worksheet above shows.

Do Roth conversions make sense once you are already retired?

Retirement is often a period when conversions fit well, because income has usually dropped into lower brackets. Conversions are allowed at any age with no earned-income requirement and no dollar limit (Source: IRS Pub 590-A, 2026). Converting before RMDs and before claiming Social Security can keep the conversion in lower brackets, though each household’s numbers differ.

How do Roth conversions affect the taxation of Social Security benefits?

A conversion raises provisional income, which can push more of your Social Security into the taxable range, up to 85% of benefits (Source: IRS Pub 915, 2026). Converting in years before you claim benefits avoids this overlap. Converting in the same year you collect can add a hidden cost as it increases the taxable share of your benefits.

Will a Roth conversion raise my Medicare premiums (IRMAA), and for how long?

It can. IRMAA uses a two-year MAGI lookback, so a conversion in 2026 could raise Part B and Part D premiums in 2028 (Source: CMS, 2026). The surcharge applies for that one year and resets as income changes. Surcharges begin above $109,000 MAGI single or $218,000 MFJ, and the tiers are cliffs.

Should I pay Roth conversion taxes from the IRA or from outside funds?

Paying from a taxable brokerage account, rather than withholding from the IRA, keeps the full converted amount growing tax-free and avoids the 10% early-distribution penalty that can apply to amounts withheld before age 59.5 (Source: IRS Pub 590-B, 2026). Using IRA dollars to pay the tax reduces the balance you are trying to move.

What is the 5-year rule for Roth conversions?

Each conversion starts its own five-year clock from January 1 of the conversion year. Withdrawing the converted principal within five years and before age 59.5 can trigger the 10% early-distribution penalty on that previously taxed amount (Source: IRS Pub 590-B, Topic 557, 2026). A separate five-year clock governs whether earnings come out tax-free.

Is there an income limit to do a Roth conversion, and when is it too late?

There is no income limit and no dollar cap on conversions, unlike Roth contributions (Source: IRS Pub 590-A, 2026). The deadline is December 31 of the tax year, not April. It is rarely “too late,” but once RMDs begin you must take the year’s required distribution first, and it cannot itself be converted.

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