What is a Roth Conversion? Rules, Taxes, and the Conversion Ladder

A Roth conversion moves money from a traditional Individual Retirement Account (IRA) or 401(k) into a Roth IRA. You pay ordinary income tax on the converted amount in the year you convert, and in exchange that money grows and, in qualified distributions, comes out tax-free later.

A Roth conversion ladder is a sequence of yearly conversions timed so that each one becomes penalty-free to withdraw after its own five-year waiting period. Traditional retirement accounts normally charge a 10% penalty on withdrawals before age 59 and a half, but converted principal escapes that penalty once it has aged five years in the Roth. By converting a slice each year and waiting out the clock, an early retiree can build a bridge that funds the years between leaving work and reaching penalty-free withdrawal age.

How a Roth Conversion Works

You ask your IRA custodian to move some or all of a traditional IRA balance into a Roth IRA, usually as a direct transfer between accounts. The custodian reports the conversion on Form 1099-R, and you report it on Form 8606 with your tax return. There is no income limit on conversions and no cap on how much you can convert in a year. The direct cost is the income tax on the pre-tax dollars you move, though the added income can also raise other costs, covered below.

Why Convert to a Roth in the First Place

The first of three common goals, which often overlap, is tax-rate arbitrage. If you expect to be in a higher tax bracket later than you are today, paying the tax now at a lower rate and letting the balance grow tax-free can leave you ahead. Early-retirement years, after paychecks stop but before required distributions start, are often a lifetime low point for taxable income.

The second is early access. Converted principal becomes penalty-free after five years, which is what makes the ladder work.

The third is reducing required minimum distributions (RMDs). Traditional IRA balances force taxable withdrawals starting at age 73 (75 if you were born in 1960 or later), whether or not you need the money, and 401(k) balances do the same once you’ve retired from the employer that sponsors the plan. Roth IRAs carry no RMDs for the original owner, so converting earlier shrinks the balance that will later be forced out.

Roth Conversion Rules and Taxes

The converted amount is added to your taxable income for the year and taxed at ordinary income rates, not capital gains rates. Any after-tax basis you hold, such as nondeductible IRA contributions, comes over tax-free, subject to the pro-rata rule below. The conversion itself carries no 10% early-withdrawal penalty.

Conversions are permanent. Before 2018 you could undo one through a recharacterization, but the Tax Cuts and Jobs Act eliminated that option for conversions made in 2018 or later, so a conversion done before a market drop can’t be reversed.

A conversion counts for the tax year in which the money leaves the traditional account. To count for 2026, it has to happen by December 31, 2026. Contributions get until the April filing deadline; conversions don’t.

Paying the tax from cash outside the IRA keeps the full amount working in the Roth. If you have the custodian withhold tax from the conversion instead, the withheld portion never reaches the Roth. It’s treated as an ordinary distribution, and if you’re under 59 and a half it can owe the 10% additional tax as well.

Because a conversion raises your modified adjusted gross income (MAGI), it can ripple into other income-tested costs. Medicare’s income-related monthly adjustment amount (IRMAA) uses your MAGI from two years earlier, so a large conversion at 63 can raise your premiums at 65. If you buy Affordable Care Act (ACA) marketplace coverage, conversion income can shrink or eliminate your premium tax credit for that year.

You don’t have to convert everything at once. One approach is filling a bracket: convert just enough to reach the top of your current tax bracket, so none of it is taxed at the next rate up. Whether that’s the right amount depends on your expected future tax rate, future RMDs, and IRMAA or ACA thresholds.

Conversions aren’t limited to IRAs. A 401(k), 403(b), or governmental 457(b) plan with a Roth option may offer in-plan Roth rollovers, which convert pre-tax plan money to the plan’s Roth account under the same income-tax treatment. Plans aren’t required to offer them.

The Five-Year Rule for Conversions

Each conversion starts its own five-year clock. The converted principal cannot be withdrawn penalty-free until five tax years have passed from the start of the year you converted it. Convert in 2026 and that batch becomes accessible in 2031.

This conversion five-year rule is separate from the five-year rule that governs whether Roth earnings come out tax-free, and it applies only while you are under 59 and a half.

Roth Conversion Ladder Example

Say you retire at 50 with a large traditional IRA and want to cover $40,000 of annual spending until you turn 59 and a half. You start converting $40,000 from the traditional IRA to your Roth IRA each year, paying income tax on each conversion at what is now a low post-retirement rate.

For the first five years you live on savings outside retirement accounts, such as a taxable brokerage account. In 2031, the 2026 conversion clears its five-year clock and you withdraw that $40,000 penalty-free and tax-free. Each following year, the next rung matures and funds another year of spending, and you keep converting at the top of the ladder to extend it. The rungs keep maturing until you reach 59 and a half, at which point the penalty disappears entirely and the ladder has done its job.

The Pro-Rata Rule Caveat

If you hold any pre-tax money in traditional IRAs, the pro-rata rule can make a conversion more taxable than you expect. The Internal Revenue Service (IRS) treats all your non-Roth IRA balances as one pool and taxes each conversion in proportion to the pre-tax and after-tax money across that pool. You cannot convert only the after-tax dollars to sidestep the tax.

This matters most when you combine conversions with a backdoor Roth IRA. For a ladder built from fully pre-tax balances, you already expect the whole conversion to be taxable.

When a Roth Conversion Ladder Makes Sense

The ladder fits best when you are retiring before 59 and a half, hold most of your savings in traditional accounts, and have taxable savings to live on during the first five years while the ladder fills. It relies on your post-retirement income being low enough to convert at a modest rate.

It fits less well if converting would push you into a high bracket, if you lack outside savings to cover the initial five-year gap, or if the added income would cost you ACA premium tax credits. You can model Roth conversions in ProjectionLab’s tax optimizer and compare strategies such as converting up to a bracket ceiling against goals like lower lifetime taxes, smaller RMDs, or reduced IRMAA surcharges.

Frequently Asked Questions

How does a Roth conversion ladder work? You convert a portion of a traditional IRA or 401(k) to a Roth IRA each year, paying income tax on each conversion. Five years after each conversion, that year’s converted principal becomes available to withdraw penalty-free and tax-free. Stagger the conversions and you create a ladder where a new rung matures every year, funding early-retirement spending until you reach 59 and a half.

When can I withdraw from a Roth conversion? The taxable part of a conversion can be withdrawn penalty-free five tax years after the year you converted it, counting from January 1 of that year. Before those five years pass, withdrawing that taxable amount under age 59 and a half generally triggers the 10% early-withdrawal penalty. Any after-tax basis that came over in the conversion isn’t subject to the penalty. After you turn 59 and a half, the conversion five-year clocks no longer apply to penalty-free access.

Do I pay taxes on a Roth conversion? Yes. The pre-tax amount you convert is taxed as ordinary income in the year you convert, but the conversion itself carries no 10% penalty.

Is a Roth conversion worth it? It tends to pay off when the rate you pay on the conversion is lower than the rate those dollars would face when withdrawn later. All else equal, converting at 12% to avoid withdrawals taxed at 22% in retirement comes out ahead; converting at 24% to avoid 12% later does not. The case gets stronger if you can pay the tax from money outside the IRA, have many years of tax-free growth ahead, or want smaller RMDs and tax-free money for heirs. It gets weaker if the conversion pushes you into a higher IRMAA tier or costs you ACA premium tax credits.

How much should I convert to Roth each year? Start with enough to reach the top of your current tax bracket without spilling into the next one. If you’re building a ladder, convert at least what you expect to spend from that rung five years later. Then check the MAGI thresholds that matter to you: IRMAA tiers from age 63 onward, because of the two-year lookback, and ACA subsidy eligibility if you buy marketplace coverage.

Roth conversion ladder vs. backdoor Roth: what is the difference? A backdoor Roth IRA is a way for high earners to fund a Roth despite income limits: you make a nondeductible contribution to a traditional IRA (the 2026 IRA limit is $7,500) and convert it right away, with little or no tax owed because the contribution was already after-tax. A Roth conversion ladder is a multi-year strategy that converts existing pre-tax balances, deliberately incurs the tax, and times each conversion so the principal becomes accessible five years later. There is no income limit on conversions themselves, so anyone can build a ladder regardless of earnings.