Converting pre-tax retirement money to a Roth IRA can save you thousands in future taxes -- but the timing has to be right. Here is how to evaluate the decision.
How a Roth Conversion Works
A Roth conversion moves money from a Traditional IRA (or other pre-tax retirement account) into a Roth IRA. The key difference between these accounts is when you pay taxes. Traditional IRA contributions are often tax-deductible going in, but you pay income tax on every dollar you withdraw in retirement. Roth IRA contributions are made with after-tax dollars, but qualified withdrawals in retirement are completely tax-free.
When you convert, you are essentially choosing to pay tax now instead of later. The converted amount is added to your taxable income for that year. If you convert $50,000, that $50,000 gets added on top of your salary and other income, and you owe income tax on it at your current marginal rate. There is no 10 percent early withdrawal penalty on the conversion itself, regardless of your age, as long as the money goes into the Roth IRA.
Once inside the Roth, the money grows tax-free forever. You will never owe taxes on the gains, and qualified withdrawals after age 59 and a half are completely tax-free. Roth IRAs also have no required minimum distributions during the owner's lifetime, giving you more flexibility in retirement and making them excellent wealth transfer tools.
Tax Implications and Ideal Timing
The central question is whether your tax rate today is lower than it will be in retirement. If yes, converting now locks in the lower rate. If your retirement tax rate will be lower, converting could cost you more than it saves. Since no one can predict future tax rates with certainty, this requires educated estimation.
The best time to convert is during low-income years. If you take a sabbatical, lose a job, retire early before claiming Social Security, or have a year with unusually large deductions, your taxable income drops and you can convert at a lower bracket. The gap between your current income and the top of your tax bracket represents a conversion opportunity. For example, if you are in the 22 percent bracket with $20,000 of room before hitting the 24 percent bracket, converting $20,000 keeps the entire conversion at 22 percent.
You can also spread conversions over multiple years. Converting $200,000 all at once could push you into the 32 or 35 percent bracket. Converting $40,000 per year over five years might keep you in the 22 or 24 percent bracket the entire time, saving thousands in total tax.
The Backdoor Roth Strategy
High earners above the Roth IRA income limits cannot contribute directly to a Roth. The backdoor Roth is a two-step workaround. First, you make a non-deductible contribution to a Traditional IRA. Then you convert that Traditional IRA to a Roth. Since the contribution was not deducted, you only owe tax on any earnings that accumulated between the contribution and conversion. If you convert quickly, those earnings are minimal.
This strategy works cleanly if you have no other Traditional IRA balances. If you do, the pro-rata rule complicates things. The IRS looks at all of your Traditional IRA balances when determining the taxable portion of a conversion. You cannot selectively convert only the non-deductible portion. If you have $95,000 in a rollover IRA (all pre-tax) and make a $5,000 non-deductible contribution, only 5 percent of any conversion is tax-free. The other 95 percent is taxable.
One solution is to roll your existing pre-tax IRA money into a 401(k) plan that accepts incoming rollovers. This removes the pre-tax balance from the pro-rata calculation, leaving only your non-deductible contribution in the Traditional IRA and making the backdoor conversion essentially tax-free.
The 5-Year Rule
Each Roth conversion has its own 5-year holding period. If you withdraw the converted amount before five years have passed and you are under age 59 and a half, you will owe a 10 percent early withdrawal penalty on that amount. This rule applies to the converted principal, not the earnings. After five years, you can withdraw the converted amount penalty-free at any age.
There is a separate 5-year rule for Roth IRA earnings. To withdraw earnings completely tax-free, the Roth account must have been open for at least five years and you must be at least 59 and a half. The five-year clock starts on January 1 of the tax year of your first Roth contribution or conversion, whichever came first. If you opened your Roth in 2020, the five-year requirement was satisfied on January 1, 2025.
When a Conversion Does Not Make Sense
Converting is a poor decision if you must use money from the IRA itself to pay the tax bill. Paying the tax from outside funds (a savings account, for instance) preserves the full converted amount inside the Roth where it grows tax-free. If you withdraw IRA money to cover taxes, you lose that growth potential and may also owe the 10 percent penalty if you are under 59 and a half.
Conversions can also be counterproductive if you are already in a high tax bracket with no low-income years expected before retirement. If you are earning peak income at the 35 percent bracket and expect to drop to the 22 percent bracket in retirement, paying 35 percent now to avoid 22 percent later is not a winning trade. Conversions shine when current rates are low relative to expected future rates, not the other way around.