A Roth conversion moves money from a pre-tax account into a Roth. You pay tax on the converted amount now — and that money grows tax-free forever.
Roth conversions are one of the most powerful tax-planning moves available to retirees and near-retirees — and one of the most misunderstood. The basic idea: you take money sitting in a traditional IRA (or 401(k), SEP IRA, SIMPLE IRA, or other pre-tax account), move it into a Roth IRA, and pay income tax on it now at your current rate. In exchange, you lock in tax-free growth and tax-free withdrawals for the rest of your life — and eliminate future RMDs on that money.
Why would someone do that? Because tax rates aren't permanent. If you expect your tax rate to be higher later — or if you're in a temporarily low-income window (early retirement, before Social Security kicks in, a year with business losses) — a conversion can lock in a lower rate than you'd pay on RMDs or distributions down the road. Many people do partial conversions each year to gradually fill up a tax bracket without triggering a big single-year hit.
The challenge is that conversions can interact with Medicare premiums (IRMAA), Social Security taxation thresholds, and capital gains rates in ways that aren't obvious upfront. Understanding the mechanics — especially the pro-rata rule and the conversion 5-year clock — is essential before pulling the trigger.
When you convert, the converted amount is added to your ordinary income for that tax year. If you convert $50,000, it's as if you earned $50,000 more that year. Set aside funds from outside the IRA to pay the tax — paying it from converted funds is generally a bad idea, especially before age 59½ (the 10% early withdrawal penalty may apply to the withheld portion). See also: Retirement Account Deadlines (December 31 conversion cutoff and related year-end dates).
If you have any pre-tax IRA money, the IRS treats all your IRAs as one pool. You can't convert only the after-tax portion. The taxable percentage of each conversion equals the ratio of pre-tax IRA funds to your total IRA balance. This trips up many backdoor Roth attempts.
Each Roth conversion has its own 5-year holding period. If you withdraw converted principal before 5 years and you're under age 59½, the 10% penalty applies to that converted amount — even though you already paid income tax on it. After 59½, this clock doesn't matter for penalties.
There is no income limit on Roth conversions. Income limits apply only to direct Roth IRA contributions. Anyone at any income level can convert. This is the mechanism behind the backdoor Roth strategy.
Medicare Part B and D premiums for high earners use MAGI from two years prior. A large conversion in 2025 shows up in your 2027 Medicare premiums. A $100,000 conversion could add $1,000+ in annual premiums. Factor this into your conversion math, especially near retirement.
Prior to 2018, you could undo a Roth conversion (recharacterize it). The Tax Cuts and Jobs Act eliminated that option. Once you convert, you cannot reverse it. Plan carefully before executing.
No. Income limits apply to direct contributions to a Roth IRA — not to conversions. Anyone can convert regardless of income. This is why the backdoor Roth works: you make a non-deductible traditional IRA contribution (no income limit), then immediately convert it to a Roth IRA.
No. The Tax Cuts and Jobs Act of 2017 eliminated the ability to recharacterize (reverse) a Roth conversion — effective for conversions done in 2018 and later. Once you convert, the decision is permanent. (You can still recharacterize a regular Roth IRA contribution, just not a conversion.)
The pro-rata rule applies to anyone with both pre-tax and after-tax money in IRAs. When you convert, the IRS treats all your traditional IRAs as a single pool. The taxable portion equals: (pre-tax IRA balance) ÷ (total IRA balance including after-tax basis).
The pro-rata rule does not apply to 401(k) accounts — only to IRA accounts. If your only traditional IRA is pre-tax, 100% of any conversion is taxable.
Each Roth conversion starts its own 5-year clock. If you withdraw the converted principal within 5 years and you're under age 59½, the 10% penalty applies — even though you already paid income tax on that money when you converted.
After age 59½, this 5-year penalty clock no longer matters. There is a separate 5-year rule for Roth IRA earnings that has different consequences — but that's a different rule.
A backdoor Roth is a two-step process for high earners who can't contribute directly to a Roth IRA: (1) make a non-deductible contribution to a traditional IRA, then (2) immediately convert it to Roth. Because the contribution was after-tax, the conversion is generally not taxable.
It works cleanly when you have no other pre-tax IRA money. If you have a large traditional IRA with pre-tax funds, the pro-rata rule makes most of the conversion taxable. Workaround: roll pre-tax IRA money into an employer plan (if accepted) before executing the backdoor.
IRMAA surcharges use your MAGI from two years prior. A large conversion in Year 1 can push your Medicare premiums into a higher bracket in Years 2 and 3. For someone converting near or in retirement, this is a real cost that must be included in the conversion math. You can appeal an IRMAA determination if your income has since dropped due to a life-changing event.
Roth accounts eliminate future RMD obligations — here's how RMDs work and why that matters.
Rolling a 401(k) to a traditional IRA is often the step before a Roth conversion strategy.
Inheriting a Roth IRA is far more valuable than inheriting a traditional IRA. Here's why.
The Rundown covers Roth conversions, rule changes, case studies, and real-world scenarios — one short issue at a time.
This guide is for general education and information only. It does not provide individualized investment, tax, or legal advice, and does not establish a client relationship. Always consult your own tax professional, financial advisor, or legal counsel before making decisions about your accounts or retirement strategy.