What to Weigh Before a Roth Conversion
A framework for thinking through the timing, amount, and tradeoffs of moving traditional retirement dollars into a Roth account — not a recommendation to convert.
Households considering whether, when, and how much to convert from a traditional IRA or 401(k) to a Roth account, including those splitting time between Arizona and another state.
Conversion decisions get made in a single tax-season conversation, but they interact with brackets, Medicare premiums, and state residency in ways that are easy to miss and impossible to undo once filed.
- How to think about filling this year's bracket versus a future one
- Where the tax on the conversion should come from
- Why converting can raise Medicare premiums two years later
- What Arizona residents and snowbirds should check before converting
- Why timing within the calendar year matters
- The case for converting in smaller pieces over several years
- Why a conversion cannot be undone once made
- What a conversion means for the people who eventually inherit the account
- 1
Compare this year's bracket to a reasonable estimate of a future one
A conversion moves income into the current tax year in exchange for potentially tax-free withdrawals later. That trade tends to look more attractive when your current bracket is lower than the bracket you expect to occupy later, for example before required withdrawals or Social Security begin. No one can know future tax law with certainty, so this is a comparison of reasonable scenarios, not a prediction.
Questions to answer- · What bracket are we in this year, and how much room is left in it?
- · What do our projected income and bracket look like once required withdrawals begin?
- · How sensitive is this decision to a change in future tax law?
- 2
Decide where the tax bill will be paid from
Converting creates taxable income for the year, and the resulting tax is generally best paid from money outside the retirement account, such as a savings or brokerage account. Paying the tax from the converted funds themselves reduces the amount that moves into the Roth and can trigger an early withdrawal penalty if you are under the applicable age. Confirm current age and penalty rules with your tax professional or irs.gov.
Questions to answer- · Do we have funds outside retirement accounts to cover the tax?
- · What happens to the analysis if we pay the tax from the IRA itself?
- · Would paying from savings affect other near-term goals?
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- Understand the two-year Medicare premium look-back
Medicare Part B and Part D premiums can be adjusted upward based on income reported roughly two tax years earlier.
Includes: “Are we within two years of enrolling in Medicare, or already enrolled?”
- Check state tax treatment, especially if you split time between states
Arizona taxes income according to its own rules, and a household that spends part of the year in another state needs to know which state will treat the conversion as taxable income and under what residency rules.
Includes: “Which state will tax this conversion, and under what residency test?”
- Consider timing within the calendar year
A conversion is generally taxed in the year it is completed, so once other income for the year is reasonably estimated, later months can be used to convert an amount that fills remaining bracket space without spilling into the next bracket.
Includes: “How much of this year's income do we already know with confidence?”
- Weigh a single large conversion against several smaller ones
Converting the full amount in one year fills brackets faster and finishes the decision, but it can push more income into higher brackets or into a Medicare look-back year than spreading the same total across several years would.
Includes: “What would filling our target bracket look like over two or three years instead of one?”
- Remember that a conversion cannot be reversed
Rules that once allowed unwinding a conversion no longer apply, so once the transfer is complete the tax consequence is set regardless of what markets or tax law do afterward.
Includes: “Are we comfortable that this decision cannot be undone once made?”
- Think about who eventually inherits the account
A Roth account generally passes to beneficiaries with different tax characteristics than a traditional account, which can matter for heirs who will themselves be subject to distribution rules on an inherited account.
Includes: “Who are the named beneficiaries on this account today?”
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Official sources
Rules change. Confirm anything that affects a decision against the current official source.
Where this fits in our work
This guide accompanies our tax-aware planning work. Joe Donti meets with Arizona households by appointment — in the Scottsdale office, by phone, or on Zoom.
Related reading
This guide is general education and is not individualized investment, tax, legal, Medicare, or insurance advice, and it is not a recommendation to buy or sell any product or security. Investing involves risk, including possible loss of principal. Insurance and annuity guarantees depend on the claims-paying ability of the issuing carrier. Rules and figures change — confirm current details with the official sources above and with your own tax, legal, or insurance professional.