Roth Conversion Ladder: 4 Real-World Case Studies

Theory is clean. Real life has messy account balances, uneven bridge funding, and expenses that don't always fit the textbook formula. Here are four case studies that show how the Roth Conversion Ladder works — and sometimes doesn't — across very different starting positions.

Each case uses the Roth Conversion Ladder Calculator for year-by-year projections. All dollar amounts are 2026 dollars with 2026 tax brackets.

Case 1: Solo FIRE at 40 — The Textbook Case

Profile: Software engineer, single, age 35, targeting retirement at 40 in a zero-tax state (Texas).

The Plan

This profile is about as close to ideal as it gets. With $350,000 in accessible bridge funds (Roth contributions + taxable) against $50,000 in annual expenses, the bridge is well over the recommended $275,000 target. There's even a healthy buffer.

Each year starting at age 40, Alex converts $50,000 from Traditional IRA to Roth IRA. After the standard deduction ($16,100), taxable income is $33,900. That falls squarely in the 12% bracket, producing a federal tax bill of approximately $4,100 per year. Texas has no state income tax, so that's the total tax cost.

Bridge drawdown during the first 5 years sources primarily from the taxable brokerage (using high-basis shares to minimize capital gains) with Roth contributions as backup. By age 45, the first conversion has matured and withdrawals begin. By age 46, the second conversion matures. From that point forward, conversions and matured withdrawals form a self-sustaining cycle.

By age 73, when RMDs would otherwise begin, the Traditional IRA has been substantially drawn down through 33 years of gradual conversions. The remaining balance is small enough that RMDs won't meaningfully affect the tax picture.

Tax Summary

Total federal tax paid on $1.65M of conversions over 33 years: ~$135,300 — an effective rate of ~8.2%. Had this money been withdrawn at Alex's working-years marginal rate of 24% (plus FICA), the tax bill would have exceeded $390,000.

Lesson Learned

This is the ideal Roth Ladder profile: robust bridge, single filer with modest expenses, zero state tax. When all three conditions are met, the ladder strategy produces extraordinary tax savings with minimal complexity.

Case 2: Couple FIRE at 50 — The Bridge Squeeze

Profile: Married couple, both 45, targeting retirement at 50 in Oregon.

The Problem

The bridge math is alarming. Accessible funds total $80,000 ($50,000 Roth + $30,000 taxable). Required bridge for $70,000 expenses: 5 × $70,000 × 1.015 = $355,250. They're $275,000 short.

The Traditional balance is also relatively modest at $500,000. Converting $70,000 per year (matching expenses) would deplete it in about 7 years — not enough runway for a lifelong strategy.

The Reworked Strategy

For this couple, a pure Roth Ladder isn't feasible. Instead, they adopt a hybrid approach:

1. Delay retirement to 52. Two more years of saving adds roughly $50,000 to the taxable account (assuming aggressive saving) and $50,000 more in Traditional contributions. Bridge improves to ~$130,000.

2. One spouse continues part-time consulting. Earning $30,000 per year reduces the bridge drawdown by $150,000 over 5 years. The earned income also helps with Social Security credits.

3. Relocate to Nevada. Moving from Oregon (9.9% state tax) to a zero-tax state saves approximately $6,900 per year on the conversion itself and reduces overall cost of living by moving to a lower-expense area.

4. Reduce conversion amount to $40,000/year. With $30,000 in earned income, converting $40,000 keeps total MAGI around $70,000. After the MFJ standard deduction ($32,200), taxable income is ~$37,800 — well within the 12% bracket. Federal tax on the conversion: ~$3,800.

5. Bridge makeup: $130,000 accessible + $30,000/year earned income effectively provides $280,000 of bridge coverage over 5 years. Tight, but workable with a modest expense buffer.

Tax Summary (Revised Plan)

Lesson Learned

The bridge is the gatekeeper. A couple with $500K in Traditional assets might want to Roth ladder, but without adequate bridge funding, the math doesn't work. The fix is a combination of earning income during the bridge, reducing expenses (including geographic arbitrage), and adjusting the timeline. The MFJ bracket advantage helps on taxes but doesn't solve the bridge problem.

Case 3: High-Income Professional — The Big Numbers Case

Profile: Married couple, both 50, targeting retirement at 55. One was a physician, the other in corporate finance. Living in New Jersey.

The Plan

At first glance, $120,000 in annual expenses looks like a problem. But with $425,000 in bridge funds ($25,000 Roth + $400,000 taxable) against a bridge requirement of approximately $660,000 (5 × $120,000 × 1.015), they're still short — but not as badly as Case 2.

The MFJ bracket is the secret weapon here. With $100,800 in the 12% bracket plus a $32,200 standard deduction, this couple can convert up to $133,000 per year while staying in the 12% bracket. Their $120,000 conversion target fits comfortably with room to spare.

The taxable account is substantial at $400,000. Using SpecID cost basis, they can sell high-basis shares during the bridge years to minimize capital gains. If the taxable account has a blended basis of 60% (meaning $240,000 is basis and $160,000 is gain), they can sell $120,000 of securities with only ~$48,000 in realized gains — which, combined with the MFJ 0% LTCG bracket of $98,900, means zero federal capital gains tax during the bridge.

Nursing the bridge: with $425,000 accessible and $120,000/year expenses, they need to stretch it for 5 years. That's $600,000 needed — a $175,000 shortfall. Options:

• Reduce expenses to $100,000. Trims bridge need to ~$507,500. Still tight.
• Sell the house and rent. They have ~$300,000 in home equity (not counted above). Selling frees up capital.
• One spouse consults for 2 years. Even $40,000/year for 24 months adds $80,000 of bridge coverage.
• Move out of New Jersey. The state tax savings alone (up to 10.75% on conversions) covers nearly $13,000/year.

Tax Summary (With NJ-to-FL Relocation)

Without state tax on conversions, the effective federal rate is roughly 7.8% — on money that was deducted at 35%+ during peak earning years. That's a 27-point tax arbitrage spread.

Lesson Learned

High expenses demand a proportionally larger bridge, but the MFJ bracket advantage provides more annual conversion room. A couple with a large taxable account and high Traditional balance can make the ladder work even at six-figure spending levels — but the bridge math must be solved first. Geographic arbitrage (especially state tax arbitrage) becomes more valuable as the numbers get larger.

Case 4: LeanFIRE at 35 — The Simplicity Case

Profile: Single, age 30, targeting retirement at 35. Lives in a low-cost Midwest city. Frugal lifestyle, no dependents.

The Plan

LeanFIRE profiles are the easiest to ladder. $140,000 in bridge funds ($60,000 Roth + $80,000 taxable) against $25,000 in annual expenses creates a bridge requirement of roughly $137,500. The bridge is exactly funded with essentially zero margin — but it works.

Annual conversions of $25,000 (matching expenses) face minimal taxation. After the standard deduction ($16,100), taxable income is just $8,900. At 10%, the federal tax bill is $890 per year.

Because the Traditional balance is only $300,000 and conversions are just $25,000 per year, the ladder will take 12 years to fully convert. That's fine — there's no rush. The low conversion amount means minimal tax drag and full ACA subsidy preservation. By age 47, every dollar of the original Traditional balance is in the Roth IRA, and the ladder is complete.

This profile also benefits from the 0% LTCG bracket ($49,450 for single filers). With only $25,000 in conversions (and $8,900 in taxable income after deductions), there's over $40,000 of 0% LTCG space remaining. If the taxable account has gains, they can be harvested entirely tax-free.

Tax Projection

Total tax on $300,000 converted: $10,680 — an effective rate of 3.6%.

If this money had been taxed at the working-years marginal rate of 22%, the tax bill would have been $66,000. The ladder saves over $55,000 on a relatively modest nest egg.

Lesson Learned

LeanFIRE is the easiest profile for a Roth Conversion Ladder. Low expenses mean a small bridge, a small annual conversion, minimal tax liability, and no bracket-filling complexity. The strategy works almost automatically — convert your annual expense amount, pay pocket-change in taxes, repeat until the Traditional balance is gone. The main risk for LeanFIRE is whether $25,000/year is sustainable for 50+ years, but that's an expense question, not a ladder question.

How the Four Cases Compare

What This Tells Us

The common thread across all four cases: the bridge determines feasibility, and the tax brackets determine efficiency.

• Case 1 and Case 4 work as textbook ladders because their bridges are funded. Case 2 requires a hybrid approach. Case 3 works but needs relocation to optimize.
• MFJ filers (Cases 2 and 3) get more annual conversion room, but that doesn't help if the bridge falls short.
• LeanFIRE profiles are almost trivially easy to ladder — minimal tax, minimal complexity, minimal bridge stress.
• Geographic arbitrage appears in three of four cases as a bridge-fixing or tax-optimizing lever.

Run your own numbers. The Roth Conversion Ladder Calculator models all of these variables — bridge sizing, conversion amounts, tax liability, and year-by-year cash flows — so you can see where your profile lands. For the complete strategy framework, read the pillar guide. For bridge funding details, see our bridge funding guide. For tax bracket strategy, read the tax optimization guide.

Your numbers won't look exactly like any of these four cases. But the principles — fund the bridge, fill the brackets, optimize for your state — apply universally.

Sources

• IRS Revenue Procedure 2025-36 — 2026 inflation-adjusted tax rate schedules, standard deductions, and capital gains thresholds
• IRS Publication 590-B — Distributions from IRAs, including Roth IRA ordering rules and conversion guidelines
• Healthcare.gov — ACA premium tax credit eligibility and income thresholds