A Roth conversion ladder is a multi-year strategy for moving money from a traditional IRA (or 401k) into a Roth IRA in incremental steps, rather than all at once. The goal is to spread the taxable income generated by conversions across several low-income years — typically early in retirement — to minimize the total lifetime tax paid.
The strategy is particularly powerful for early retirees who have a gap between leaving work and the age when Social Security, pensions, and RMDs begin. During those low-income years, you can convert at the 10% or 12% federal rate instead of paying 22% or higher on forced RMD withdrawals decades later.
Why Convert at All?
Traditional IRA and 401(k) withdrawals are taxed as ordinary income. The larger your required minimum distributions (RMDs) in your 70s and 80s, the higher your tax bracket and the more of your Social Security that becomes taxable. By converting while your income is low — before Social Security, before RMDs, before pension income begins — you pre-pay taxes at a lower rate.
There is also a legacy benefit. Roth IRAs have no RMDs during the original owner's lifetime, and inherited Roth IRAs pass to beneficiaries tax-free (though the SECURE Act requires most non-spouse beneficiaries to empty the account within 10 years). If leaving tax-efficient wealth to heirs is a goal, Roth conversions move assets into the most favorable account type.
The Mechanics of the Ladder
Identify your income each year and determine how much room remains in your current tax bracket. The goal is to convert up to the top of a bracket without spilling into the next. For example, if you are in the 12% bracket and have $30,000 of room before reaching the 22% threshold, convert $30,000 of your traditional IRA each year.
Repeat this every year during your low-income window. Over 5 to 10 years, you can move $150,000 to $300,000 or more into your Roth IRA at a fraction of the tax cost you would have paid if it came out as RMDs. The key is consistency — a little each year adds up to a lot over a decade.
Converting systematically over 5–10 years can reduce lifetime taxes by tens of thousands of dollars compared to doing nothing and paying RMD-driven rates in your 70s.
A Step-by-Step Example
Consider a married couple who retires at 60 with $1.2 million in a traditional 401(k), $200,000 in taxable savings, and no pension. They plan to claim Social Security at 67. From age 60 to 66, their only income is from taxable account withdrawals for living expenses — putting them in a very low tax bracket.
In 2025, a married couple filing jointly can earn up to $96,950 in taxable income before leaving the 22% bracket. After the standard deduction of $30,000, that means up to roughly $127,000 of gross income stays at 22% or below. If their living expenses produce $40,000 of taxable income, they have $87,000 of room to convert at the 12% and 22% rates. Converting $87,000 per year for seven years moves over $600,000 to Roth — dramatically reducing future RMDs.
The 5-Year Rule
Each Roth conversion starts its own 5-year clock. If you are under 59½, you must wait 5 years from the conversion date to withdraw those converted funds penalty-free. This is separate from the 5-year rule that governs earnings. If you are 59½ or older, the 5-year waiting period for conversions does not apply to penalty-free access.
For early retirees under 59½, this means you need to fund living expenses from other sources (taxable accounts, cash reserves) during the 5-year seasoning period. This is why the strategy is called a "ladder" — each year's conversion becomes accessible five years later, and after the first five years, you have a new rung maturing every year.
The Pro-Rata Rule
If you have both pre-tax and after-tax (non-deductible) contributions in your traditional IRAs, the IRS applies the pro-rata rule to any conversion. You cannot cherry-pick only the after-tax dollars to convert tax-free. Instead, each conversion is treated as a proportional mix of taxable and non-taxable funds based on the ratio across all your traditional IRAs.
For example, if your total traditional IRA balance is $200,000 and $20,000 is from non-deductible contributions, then 10% of any conversion is tax-free and 90% is taxable. One workaround: if your employer plan accepts incoming rollovers, you can roll the pre-tax portion into the 401(k) and convert only the after-tax remainder through the "backdoor" Roth strategy.
IRMAA and Medicare Considerations
Large conversions can push your Modified Adjusted Gross Income above Medicare IRMAA thresholds, triggering surcharges on Part B and Part D premiums two years later. Model your conversions carefully against the IRMAA brackets — especially the cliffs — to avoid inadvertently increasing your Medicare costs.
For example, a single filer converting $80,000 on top of $40,000 of other income would have a MAGI of $120,000 — above the 2026 Tier 1 threshold of $106,000. That pushes the 2028 Part B premium from the standard amount to the Tier 1 surcharge, costing several hundred dollars more per year. Often it is worth stopping the conversion $5,000 below the cliff to avoid this.
ACA Subsidies and Conversions
If you are retired before 65 and on a marketplace health plan, Roth conversions increase your MAGI — which is the same number that determines your ACA premium subsidies. Large conversions can reduce or eliminate your Premium Tax Credit, effectively adding thousands of dollars in health insurance costs on top of the conversion tax. For early retirees on the ACA, this creates a three-way optimization between tax brackets, ACA subsidy cliffs, and conversion amounts.
The ACA subsidy cliff was eliminated for 2021–2025 by the American Rescue Plan and Inflation Reduction Act, but the enhanced subsidies are currently scheduled to expire after 2025. If they revert, income above 400% of the federal poverty level ($62,160 for a single filer in 2025) would result in a complete loss of subsidies — making conversion planning even more critical for early retirees in that income range.
State Tax Considerations
Federal tax is not the only cost of conversion. Most states tax Roth conversions as ordinary income. However, some states — including Florida, Texas, Nevada, Wyoming, and others — have no state income tax at all. If you plan to relocate in retirement, converting after moving to a no-income-tax state can save an additional 4% to 13% on the conversion amount depending on the state you are leaving.
When the Ladder Makes Sense
- You retire before 65 and have several years of low-income before Social Security begins.
- Your traditional IRA balance is large enough to generate significant RMDs at 73.
- You expect tax rates to be higher in the future than they are today.
- You want to leave tax-free assets to heirs.
- You have healthcare coverage that is not tied to income (so ACA subsidy cliffs are not a concern).
Common Mistakes to Avoid
- Converting too much in a single year and jumping into a higher tax bracket or triggering IRMAA.
- Paying the conversion tax from the IRA itself instead of from outside funds — this reduces the amount that grows tax-free and may trigger a 10% early withdrawal penalty if you are under 59½.
- Ignoring the pro-rata rule when you have non-deductible IRA contributions.
- Forgetting that conversions affect ACA premium subsidies if you are on a marketplace plan before Medicare eligibility.
- Not accounting for state taxes in the total conversion cost.
Frequently Asked Questions
Is there a limit on how much I can convert in a year?
No. Unlike Roth IRA contributions, there is no income limit or annual cap on Roth conversions. You can convert $10,000 or $1,000,000 in a single year. The only constraint is the tax bill — converting more means paying more tax upfront.
Can I undo a Roth conversion?
No. Before 2018, you could "recharacterize" (undo) a Roth conversion by the tax filing deadline. The Tax Cuts and Jobs Act eliminated this option permanently. Once you convert, it is done — which makes careful planning before conversion especially important.
Should I convert if I expect to be in a lower bracket in retirement?
Not necessarily. The ladder works best when you can convert at a lower rate than you would otherwise pay on RMDs. If your retirement income will genuinely be lower than your current income and you expect to withdraw at the 10% or 12% rate anyway, the benefit of converting now at 22% is negative. Run the numbers for your specific situation.
What about the 2026 tax bracket sunset?
The individual tax cuts from the 2017 Tax Cuts and Jobs Act are scheduled to expire after 2025 unless Congress acts. If rates revert to pre-2018 levels, the 12% bracket becomes 15%, the 22% bracket becomes 25%, and so on. This potential increase makes 2025 conversions especially attractive — you may be converting at the lowest rates you will see for the foreseeable future.