The Gap-Year Roth Conversion Strategy | Education

For many retirees, the years between when wage income stops and when Required Minimum Distributions begin are the lowest-tax years of their adult life. Wage income has stopped. Social Security may not have started yet. RMDs from pretax accounts are still years away.

This is the gap year window. It's the cheapest tax-planning window most retirees will ever have, and Roth conversions are the primary lever to use it. This article walks through how to identify the window, size conversions, and orchestrate across multiple years.

Identifying your gap-year window

The window has a clear start and end:

Start: the year your wage income materially drops. For most full retirees this is "the year of retirement" or the year after. For partial retirees, it's the first year wage income falls below a threshold where ordinary tax brackets start to feel narrow.
End: the year RMDs begin to dominate income. Under SECURE 2.0, RMDs begin at age 73 (rising to 75 for those born in 1960 or later under current law).

For a typical retiree retiring at 65 with FRA-67 Social Security and no pension, the window has three sub-phases:

Phase 1 — pre-Social Security (ages 65–67 or 65–70 if delaying SS): Pure gap-year. Income comes from pretax withdrawals + after-tax investment income. Lowest projected MAGI of any phase.

Phase 2 — post-Social Security claiming, pre-RMD (ages 67–73 or 70–73): Social Security has started. MAGI rises by the taxable portion of SS benefits. Still well below RMD-driven MAGI.

Phase 3 — RMD years (ages 73+): RMDs from pretax accounts force substantial taxable income. The taxable Social Security portion may hit the 85% maximum. MAGI is at lifetime peak.

The conversion strategy uses Phases 1 and 2 to convert money into Roth before Phase 3's RMDs increase your tax cost.

Why the window matters — the rate-arbitrage thesis

The strategic case for gap-year conversions rests on rate arbitrage:

Convert when your current marginal rate is lower than your expected future marginal rate when the money would otherwise be withdrawn.

Three forces tend to make the future rate higher:

RMDs force withdrawals. Without conversion, all the pretax money eventually comes out as RMDs starting at 73. RMDs are taxed as ordinary income. The pile of pretax assets that didn't convert becomes a high-marginal-rate problem in the 70s+.
Social Security taxability rises with other income. As pretax withdrawals increase (driven by RMDs), more of your Social Security becomes taxable, up to the 85% ceiling. This effectively raises the marginal rate on every additional dollar of pretax withdrawal.
Survivor tax-bracket compression. When one spouse dies, the survivor files single — same RMD income, but compressed into the single-filer brackets. Marginal rates jump materially. For couples with significant pretax balances, this is a real but often-modeled-too- late tax-rate increase.

If your projected Phase-3 marginal rate is meaningfully higher than your gap-year marginal rate, conversions during the gap years are positive-expected-value.

Phase-1 conversions — fill the lowest brackets

In Phase 1 (pre-Social Security, pre-RMD), your primary income source is your withdrawals from pretax accounts. You can size those withdrawals to fill specific tax brackets cheaply.

Strategy for Phase 1:

Withdraw from pretax accounts to cover spending needs.
Roth-convert on top of the spending withdrawals to fill cheap brackets.
Stop converting at whichever ceiling binds first:
- The next federal-bracket boundary (typically 12% → 22%, or 22% → 24%)
- The IRMAA Tier-0 → Tier-1 boundary (if you're within 2 years of Medicare eligibility — see IRMAA cliff strategy)
- The next ACA premium tax credit cliff (if you're under 65 and on Marketplace insurance — ACA MAGI tier sensitivity is an additional constraint)

Worked example — 65-year-old single retiree, $70k spending need:

Spending withdrawal from pretax: $70,000
Standard deduction (single): about $15,000
Taxable income before conversion: $55,000
2026 single-filer top of 12% bracket: about $48,475
2026 single-filer top of 22% bracket: about $103,350

To stay in 12%: not possible (taxable income already $55k after spending withdrawal). The household is already at 22% on the marginal dollar. Converting more pushes deeper into 22%.

To fill 22%: convert up to $103,350 − $55,000 = $48,350.

A $48,350 conversion costs $48,350 × 22% = $10,637 in federal tax, funded from the conversion year's other resources.

If the household's projected Phase-3 rate is 24% or higher (likely with significant pretax balances), the conversion captures a 2%+ rate- arbitrage gain on the converted dollars. Compounded tax-free over 8+ years, the conversion is meaningfully positive.

Phase-2 conversions — Social Security has started

Once Social Security claims start, the gap-year strategy continues but gets more complicated:

Social Security adds to MAGI and pushes more of itself into the taxable portion (the "tax torpedo" effect).
For Medicare-eligible filers, IRMAA tier sensitivity is now a binding constraint. Conversions that exceed the next IRMAA boundary add a 2-year- later premium surcharge cost.
The federal-bracket headroom is smaller because Social Security itself is using some of the bracket capacity.

Strategy for Phase 2:

Continue converting as long as the rate-arbitrage thesis holds.
Tighten the IRMAA tier discipline — convert to the boundary, not past it (see IRMAA cliff strategy).
Reassess each year: as RMD age approaches, the runway for conversions shrinks. By Phase 3 (RMDs active), most of the conversion opportunity has closed.

Don't pause converting just because Social Security started. The rate-arbitrage thesis still holds; you just need to model it more carefully.

Multi-year orchestration

The gap-year strategy isn't a single conversion decision. It's a multi-year orchestration where:

Each year's conversion size is chosen to fill the cheap brackets available that year, given that year's other income.
The cumulative effect across the window is to materially deplete the pretax balance before RMDs start.
The endgame is a household that arrives at age 73 with lower forced RMDs than it would otherwise have, because more of the pretax pile is now in Roth.

A common multi-year pattern for a married couple retiring at 65 with $1.5M in pretax accounts:

Year	Age	Phase	Annual conversion	Fed rate	IRMAA tier	Cumulative converted
2026	65	Pre-SS	$80,000	22%	n/a (not yet 65 for Medicare in some cases)	$80,000
2027	66	Pre-SS	$80,000	22%	Tier 0	$160,000
2028	67	Pre-SS, FRA reached	$80,000	22%	Tier 0	$240,000
2029	68	Delayed SS, still gap	$70,000	22%	Tier 0	$310,000
2030	69	Delayed SS, still gap	$70,000	22%	Tier 0	$380,000
2031	70	SS starts	$50,000	22%	Tier 1 boundary management	$430,000
2032	71	Post-SS	$40,000	22%	Tier 1 boundary	$470,000
2033	72	Final pre-RMD year	$30,000	22%	Tier 1 boundary	$500,000
2034	73	RMDs begin	minimal/none	24-32%	Tier 2-3	$500,000

Across 8 gap years, this household converts $500,000 from pretax to Roth. At Phase 3, their RMD base is materially smaller; their forced taxable income is lower; their Social Security taxability is lower; their IRMAA exposure is lower. The cumulative effect is hundreds of thousands of dollars of lifetime tax savings (and increased after-tax legacy for heirs).

Sizing decisions across the window

Three key heuristics:

1. Convert more in early years, less in late years. Early gap-year conversions have more time to compound tax-free in Roth. Late conversions have less runway. Front-loading the conversion schedule extracts more value.

2. Match conversion size to the binding constraint, not the easiest ceiling. If the federal-bracket boundary is at $103k and the IRMAA boundary is at $90k (because you're within 2 years of Medicare), the binding constraint is $90k. Stop there.

3. Coordinate with charitable-giving plans. If you're charitably inclined, Qualified Charitable Distributions (QCDs) from pretax accounts are higher-leverage than Roth conversions for the giving portion of your portfolio. QCDs reduce RMDs without ever creating taxable income. Convert what you'd keep; give what you'd give. Don't convert dollars destined for charity.

When NOT to do gap-year conversions

The strategy isn't universal. Skip or scale back when:

Your pretax balance is small. If pretax assets are $200k or less and most of your retirement money is already after-tax, the RMD problem is small and conversion benefit is correspondingly small.
Your projected Phase-3 rate is already low. If you have a small pretax balance, modest Social Security, and modest other income, your Phase-3 marginal rate may be 12% — the same as your gap-year rate. Rate arbitrage is zero.
You're already in a high bracket in the gap years. If you have significant pension income, large after-tax investment income, or continued part-time consulting earnings, your gap-year rate may be the same as your Phase-3 rate. Skip conversion until lower-rate years.
Charitable giving covers most of your pretax balance. If you plan to use QCDs heavily in retirement, conversion competes with QCD capacity. Plan QCDs first; convert what's left.
You have very limited liquid funds outside the pretax account. A conversion's federal tax has to be paid from somewhere. Paying it from the converted money itself defeats the strategy (it's effectively a withdrawal). Paying from after-tax savings is the right path. If you don't have after-tax savings to fund the tax, conversions are harder to execute.

The honest take

The gap-year Roth conversion strategy is one of the highest-leverage moves in tax-aware retirement planning, but it's not free and not universal. The case is strong for households with:

Significant pretax balances ($500k+)
A multi-year low-tax window (typically 5–10 years)
After-tax savings to fund the conversion tax
Reasonable longevity expectations
Limited alternative high-leverage strategies (no large QCDs planned, no significant pension income filling the brackets already)

For households outside this profile, conversions still have a place but the cumulative benefit is smaller, and other strategies (delay Social Security, optimize withdrawal sequencing, plan QCDs) often have more leverage.

The free Roth Conversion Decision Explorer walks through a quick assessment of whether your situation fits the gap-year profile. For multi-year orchestration with full plan integration, the planning workspace at app.nestpilot.org has deeper math.

Primary sources

This article is published by NestPilot Foundation Inc. — a nonprofit (501(c)(3) filing in progress). Multi-year orchestration is highly situation-dependent. For decisions tied to a specific situation, work with a fiduciary financial planner or CPA. The Foundation's tools provide directional analysis; they don't replace personalized advice.