Roth Conversion After Retirement

You can convert to Roth at any age, and for many retirees the years between the last paycheck and required minimum distributions (RMDs) at 73 (75 if born in 1960 or later) are the best conversion window they will ever have. There is no age limit and no income cap: the converted amount from a traditional individual retirement account (IRA) or 401(k) is added to your ordinary income for that year, taxed at a rate you can see in advance.

Why Retirement Opens the Conversion Window

When wages stop, taxable income often drops to its lowest point in decades. Delay Social Security, and before RMDs begin (age 73 or 75 under current law, depending on birth year), what remains is investment income and whatever you choose to withdraw. The 22% federal bracket in 2026 runs to $211,400 of taxable income for married filers; the 24% bracket extends to $403,550. The room between your income and the top of a bracket can be filled with a conversion at a known rate.

RMDs are not voluntary. Once they start, they stack on top of Social Security (up to 85% of which may be taxable) and everything else that arrives without your permission. A conversion trades a known rate today for an unknown, often higher, rate later.

What Else Rises With Your Income

Four other things move when your income does:

Income-Related Monthly Adjustment Amount (IRMAA). Medicare Part B and Part D premiums are means-tested on a 2-year look-back: a large conversion in 2026 affects 2028 premiums. A couple crossing the first threshold ($218,000 of modified adjusted gross income, or MAGI, for 2026 premiums) pays more per month per person for the one year that income is used (about $81 more per person for Part B at the first 2026 tier).

Social Security taxation. If you are already drawing benefits, a conversion raises provisional income and can push more of your benefit into taxable territory, so each converted dollar costs more than the marginal rate suggests.

The 5-year rule. Each conversion has its own 5-year clock for the 10% penalty on the converted amount if you are under 59½. Earnings come out tax-free once you are past 59½ and your first Roth IRA has been open 5 tax years. Past 59½ with a Roth at least 5 years old, this largely stops mattering.

State taxes. A conversion that looks attractive federally can be less compelling after state income tax, especially if a move to a no-income-tax state is coming.

The right amount fills the bracket, stops before a cliff, and accounts for future years, which takes a year-by-year calculation.

An Illustrative Example

Consider a hypothetical married couple, both 66, recently retired and delaying Social Security until 70, with $30,000 in portfolio dividends, $1.4M in a traditional IRA, and $200,000 in taxable brokerage.

Their room before the 24% threshold exceeds $200,000, so the binding constraint is the first IRMAA tier at $218,000 of MAGI, which caps one year's conversion near $185,000 after the $30,000 of dividends. Converting $150,000 to $180,000 annually for 4 years could move $600,000 to $720,000 into Roth well before RMDs begin (age 75 for this couple, born in 1960). Using 2026 brackets, the deductions for two spouses 65+, and the senior deduction, the federal cost works out to a blended rate of roughly 11% to 13%, including the conversion pushing their dividends from the 0% rate to 15%. A single $700,000 conversion instead would reach the 35% bracket, trigger one of the highest IRMAA tiers, and create a large April tax bill with no withholding offset.

How This Connects to the Roth Conversion Strategy

Converting after retirement is one slice of a larger set of decisions: how much, in which years, against which other income events, and in which accounts. For the full bracket math and the Affordable Care Act (ACA) interaction, see the parent guide: Roth Conversion: A Practical Guide for High Earners and Pre-Retirees.

Frequently Asked Questions

Is there an age limit on Roth conversions after retirement?

No, and conversions remain available even after RMDs begin at 73 or 75. You cannot convert the RMD itself, but any amount above the RMD is eligible.

Should I pay the conversion tax from the converted amount or from outside funds?

Outside funds, generally. Tax withheld from the conversion never reaches the Roth, so the benefit shrinks by exactly that amount.

Can I undo a Roth conversion if I change my mind?

No. Recharacterization of conversions was eliminated by the Tax Cuts and Jobs Act in 2018, so a conversion is permanent in the tax year it occurs.

Does a Roth conversion count as income for ACA subsidy purposes?

Yes. For early retirees under 65 on marketplace coverage, a large conversion can push MAGI above the subsidy cliff, one of the most commonly overlooked conversion watchouts. The enhanced credits expired after 2025, so for 2026 the cliff at 400% of the federal poverty level is back: one dollar over it ends the credit entirely.

What to Do Next

1. Pull your most recent tax return and identify your current MAGI and how much bracket space sits between your income and the next threshold (24% bracket top, first IRMAA cliff).
2. Project your income from your RMD age forward: estimated Social Security, RMD amounts from your pre-tax accounts, and any other expected sources. That picture tells you what the problem is if you do nothing.
3. If the gap between now and your RMD age is at least three years and your pre-tax balance is large, a year-by-year conversion model is worth building. That's where a fiduciary advisor earns the conversation.
4. If you're not working with an advisor yet, use the analysis above as a checklist to pressure-test any proposal you receive. The right plan will account for IRMAA, Social Security taxation, and state taxes alongside the federal bracket math.

The information provided is for educational purposes only and does not constitute investment, legal, or tax advice. Tax law changes frequently, so verify current rules before acting. Consult with qualified professionals for guidance specific to your situation.