Delay Social Security Roth Conversion Runway

Choosing to delay Social Security to fund Roth conversions uses the low-income years between retiring and claiming benefits as a deliberate window to move traditional IRA money into a Roth at a low tax cost. This page is about the timing decision, not the definition of a conversion: when the window opens, how long your runway lasts, and how much many retirees consider converting each year with the 2026 numbers.

Last reviewed: August 2026 | Written and reviewed by Craig Wear, CFP®, founder of Q3 Advisors

Why delaying Social Security opens a Roth conversion runway

Delaying Social Security postpones a large, partly taxable income stream. Paired with being retired and not yet subject to required minimum distributions, that creates a stretch of unusually low taxable income. Those low-income years are the runway: bracket space you can fill with Roth conversions taxed at 10% or 12% instead of the higher rates that arrive after benefits and RMDs begin.

The gap years: retired, pre-RMD, and pre-claim

During a working career, wages fill the tax brackets. In retirement, before benefits and before required minimum distributions (RMDs), taxable income can drop sharply. That valley, roughly from your early sixties until RMDs begin at age 73, is often the lowest-income stretch of an adult life, and the cheapest time in tax terms to recognize income on purpose. A Roth conversion is taxable ordinary income in the year you do it.

Two effects from one decision

Delaying benefits produces two effects at once. First, each year of delay past full retirement age adds delayed retirement credits of about 8%, up to age 70. Second, because that benefit is not yet flowing, provisional income stays low, leaving bracket headroom to convert. The tradeoff is that you draw down other assets earlier to live on and pay the conversion tax. Q3’s overview of the Roth conversion strategy connects the pieces.

What is the conversion window between retirement and Social Security?

The conversion window is the span between the year you stop working and the year your income climbs back up, whether from claiming Social Security or from required minimum distributions at age 73. For many retirees it opens in the early to mid sixties and can last five to eight years. The longer you delay benefits, the longer the window stays open, up to the RMD wall at 73.

When it opens and when it closes

The window tends to open when earned income stops, often in the early sixties. It narrows the moment you claim Social Security, because up to 85% of benefits can become taxable and fill bracket space you were using to convert. It closes at age 73, when RMDs begin. RMDs must be taken first and cannot themselves be converted, so they crowd out low-bracket room. See Q3’s guide to the 2026 RMD rules.

How long is your runway?

Your runway length is roughly your planned claim age minus your retirement age, with RMDs at age 73 as the outer wall no matter when you claim. Delaying to 70 generally leaves the most room to convert, while retiring later shortens the runway. The table below tabulates illustrative runways by retire age and claim age.

Figures are illustrative. The roomiest conversion space is usually before benefits begin.

Should you wait on Social Security to convert to Roth?

Waiting can make sense when you hold a large pre-tax balance, have other cash to live on and to pay the conversion tax, and expect a long retirement. It makes less sense when you need benefit income now, your IRA is modest, your longevity outlook is poor, or a conversion would spike costs elsewhere. The framework below weighs those factors so you can judge your own case.

When delaying tends to pencil out

Several conditions tend to line up in favor of using the gap years to convert. In broad terms, delaying and converting tend to work well when you hold a sizable pre-tax balance, have separate money to cover both living costs and the conversion tax, and expect a retirement long enough for the larger benefit and the tax-free growth to matter. The specific factors many investors weigh are below.

• A large traditional IRA or 401(k) that would otherwise drive big RMDs and high future brackets.
• Enough taxable-account cash to cover living costs and the conversion tax without raiding the IRA in a way that defeats the purpose.
• A reasonable expectation of longevity, so the larger delayed benefit and the tax-free Roth growth both have time to matter.
• A goal of leaving tax-free assets to heirs, since inherited Roth balances generally come out tax-free.

When it may not

Delaying is not a fit for everyone, and forcing it can add cost rather than benefit. It tends to make less sense when you need the benefit income now and have no separate cash to bridge the gap, when your IRA is modest enough that future RMDs stay in low brackets anyway, or when a health picture shortens the payoff period. Common reasons many investors claim earlier or convert less include:

• You need Social Security income now to cover expenses and have no separate cash to bridge the gap.
• A modest IRA, where future RMDs would likely stay in low brackets anyway, so the conversion savings are small.
• A health or family-history picture that shortens the expected payoff period for both delay and conversion.
• A conversion that would push you over an important cliff, such as the 3.8% net investment income tax above $200,000 single or $250,000 joint, or the loss of Affordable Care Act premium credits before age 65.

The tax torpedo you may sidestep

The Social Security tax torpedo is the effect where adding income once benefits are flowing makes more of those benefits taxable, so each extra dollar can be taxed at a marginal rate well above its stated bracket. Converting before you claim recognizes that income while no benefit is being taxed, so the torpedo does not apply to the conversion. Recognizing income in the gap years keeps the marginal cost near the stated bracket rate.

How much can you convert each gap year? The 2026 bracket math

Two questions drive the plan: how many low-income years you have before benefits and RMDs push income up, and how large a conversion fits inside a target bracket each year. A common approach is bracket-filling: converting just enough to reach the top of the 12% or 22% bracket without spilling into the next one. The 2026 IRS figures below make that concrete.

Bracket-filling with the 2026 figures

Bracket-filling means converting up to the top edge of a chosen bracket, measured in taxable income. Adding the standard deduction back shows roughly how much gross income (including the conversion) fits underneath. For 2026 the standard deduction is $16,100 single and $32,200 for a married couple filing jointly, with an extra $2,050 single or $1,650 per spouse at age 65 and older.

Source: 2026 IRS inflation adjustments (Rev. Proc. 2025-32). Q3’s guide on how much to convert to Roth walks through choosing a target bracket.

A worked multi-year example

Consider an illustrative single retiree, call her Susan, age 63, with $25,000 of interest and dividends and no wages. Her standard deduction is $16,100, so $8,900 of that income is taxable before any conversion. To reach the top of the 12% bracket ($50,400 taxable), she can convert about $41,500 in the year, roughly 12 cents of tax per dollar converted. Across four gap years that is about $166,000 moved to Roth.

If instead she fills to the top of the 22% bracket ($105,700 taxable), she could convert closer to $96,800 per year. A married couple has more room. With similar other income, filling to the top of the 12% bracket ($100,800 taxable) can support a larger yearly conversion. A frequently cited illustration is a couple converting about $75,000 per year for four years, roughly $300,000 moved, while staying inside the 12% and 22% bands. Every figure here is a hypothetical example used to explain a concept, not a projection of your result.

How gap-year conversions shrink future RMDs

Every dollar converted leaves the traditional IRA, so it never becomes a future RMD. Illustratively, a $1,000,000 IRA at age 73 produces a first RMD near $37,700 (Uniform Lifetime Table divisor 26.5). Reducing the balance to about $700,000 through gap-year conversions drops that first RMD to roughly $26,400, about $11,300 lower (before growth). Lower RMDs can mean lower lifetime brackets and less exposure to the tax torpedo later.

The math is illustrative and ignores growth. Note that RMD age is 73 now and rises to 75 for those born in 1960 or later, with the earliest age-75 RMD year in 2035.

Guardrails: IRMAA, ACA cliffs, and provisional income

Filling a bracket is not the only limit on a gap-year conversion. Three thresholds can raise the true cost well beyond the stated bracket rate: the Medicare IRMAA two-year lookback, the Affordable Care Act subsidy cliff before age 65, and the statutory provisional-income thresholds that decide how much of your benefit is taxed once you claim.

The 2026 thresholds to watch

Each of these thresholds is measured against your modified adjusted gross income, which a conversion raises, so a single large conversion can trip more than one at a time. The three that most often catch gap-year converters are the Medicare IRMAA surcharge lookback, the Affordable Care Act subsidy cliff before age 65, and the provisional-income thresholds that tax your benefit once you claim. Here is how each works in 2026:

• IRMAA lookback. Medicare income-related surcharges use a two-year lookback, so a conversion at 63 can raise Part B and Part D premiums at 65. For 2026, surcharges begin above $109,000 MAGI single and $218,000 joint; the standard Part B premium is $202.90. The last conversion year that does not affect a premium is age 62.
• ACA subsidy cliff. If the enhanced premium tax credits expire as scheduled for 2026, the hard cutoff at 400% of the federal poverty level returns, so a conversion before age 65 that pushes income over that line can cost the entire credit.
• Provisional income. Once you claim, 2026 thresholds of $25,000 and $34,000 (single) or $32,000 and $44,000 (joint) determine how much of the benefit is taxed, up to 85%. These thresholds are set by statute and are not indexed for inflation, so more retirees cross them every year.

Putting it together: an illustrative gap-year sequence

One illustrative sequence ties the pieces together: retire, live on cash and taxable accounts, convert to the top of a chosen bracket each gap year, then claim Social Security at 70 with a larger benefit and a smaller pre-tax balance. The steps many investors follow, with links to the mechanics of timing and break-even, run in this order:

1. Mapping the runway: retirement age, planned claim age, and the RMD wall at 73.
2. Confirming that non-IRA cash can cover living costs and the conversion tax through the gap.
3. Choosing a target bracket, often the top of 12% or 22%, and sizing each year’s conversion to it.
4. Converting before December 31 each year, since a conversion is irreversible, with no recharacterization since 2018. See the 2026 conversion deadline for timing.
5. Watching the guardrails: the IRMAA lookback, ACA credits before 65, and net investment income tax.
6. Claiming Social Security at the age longevity and cash flow support, up to 70.
7. Weighing the delay itself against the conversion payoff using a break-even analysis.

Frequently asked questions

Should I delay Social Security to do Roth conversions?

Delaying can make sense when you hold a large pre-tax IRA, have separate cash to live on and pay the conversion tax, and expect a long retirement. The delay keeps provisional income low, so you can convert at the 10% or 12% rate and grow a bigger benefit of about 8% per year to 70. It fits less well if you need the income now or your IRA is modest.

Is it better to do Roth conversions before or after starting Social Security?

For many retirees, converting before you claim is the lower-cost window. Once benefits flow, up to 85% of them can become taxable, and each converted dollar also drags more benefit into tax, the tax torpedo effect, pushing the marginal rate well above the stated bracket. Converting in the gap years, before you claim and before RMDs at 73, keeps the cost near the bracket rate.

At what age should you stop doing Roth conversions?

There is no fixed age, but the low-cost window generally closes at 73 when RMDs begin, since RMDs must come out first and cannot be converted. Many retirees also slow conversions two years before age 65 because the IRMAA two-year lookback means a conversion at 63 can raise Medicare premiums at 65. Converting after RMDs start is still allowed, just usually less efficient.

Do Roth conversions affect Social Security benefits?

A Roth conversion does not change your Social Security benefit amount, but it raises your provisional income for the year, which can make more of any benefit you are already receiving taxable, up to 85%. That is why many retirees convert in the gap years before they claim. A qualified Roth withdrawal later is not counted in provisional income at all.

How much can I convert to a Roth IRA without paying taxes?

A conversion is taxable ordinary income, so it is rarely fully tax-free, but the first dollars can be covered by your standard deduction: $16,100 single or $32,200 joint for 2026, plus the age-65 addition. Beyond that, bracket-filling to the top of the 12% band ($50,400 single, $100,800 joint in taxable income) keeps the rate low. A conversion is uncapped and cannot include an RMD.

Does delaying Social Security to 70 make sense?

Delaying to 70 raises the benefit by delayed retirement credits of about 8% per year past full retirement age, roughly 24% above the FRA benefit and as much as about 77% above a benefit claimed at 62. Published break-even ages commonly fall in the early to mid eighties. If you expect to live past your personal break-even and can bridge the gap with other assets, delaying often adds lifetime income.