I’m already taking required minimum distributions from my IRA, but I’m wondering whether it still makes sense to convert additional money to a Roth IRA. What factors should I look at, and is it usually better to convert gradually over time rather than all at once?
Many retirees assume Roth conversions stop making sense once required minimum distributions begin, but that’s often not the case. In fact, some of the best opportunities for Roth conversions happen during the years after RMDs start.
The key is understanding how the conversion affects your taxes now compared to what may happen later. In many cases, spreading conversions across several years is the most practical approach, but the right strategy depends on your income, account balances, tax situation and long-term goals.
Let’s walk through the major issues you should evaluate.
Understanding the Relationship Between RMDs and Roth Conversions
Required minimum distributions (RMDs) are mandatory withdrawals from pre-tax retirement accounts like traditional IRAs and 401(k)s. Under current rules, most people must begin taking them at age 73, though that age is scheduled to increase to 75 for some future retirees.
The amount you must withdraw each year is based primarily on your account balance at the end of the previous year and your age. Those withdrawals are generally taxable as ordinary income.
Roth IRAs work differently. Original account owners are not subject to lifetime RMDs, which is one reason Roth accounts can provide more flexibility later in retirement.
Converting money from a traditional IRA to a Roth IRA reduces the balance that will eventually be subject to future RMDs. That can potentially lower future taxable income and give you greater control over when and how you access retirement funds.
One Important Rule: Your RMD Cannot Be Converted
One point that often causes confusion is that the RMD itself is not eligible for conversion.
Suppose your IRA balance produced a $7,000 required minimum distribution for the year. That $7,000 must come out first and be treated as a taxable withdrawal. You cannot move that required amount directly into a Roth IRA as a conversion.
However, you can still convert additional IRA money after satisfying the RMD.
For example, imagine you take your required $7,000 withdrawal and then choose to convert another $20,000 to a Roth IRA. The conversion reduces the remaining tax-deferred balance in the account, which may help lower future RMDs.
Over time, repeated conversions can significantly reduce the size of future mandatory withdrawals.
Comparing Taxes Today Versus Taxes Later
The basic Roth conversion analysis comes down to one central question:
Will paying taxes now likely be better than paying taxes later?
If your tax rate today is lower than what you expect in the future, a conversion may make sense. If your future tax rate is expected to be lower, delaying taxes may be preferable. That sounds simple in theory, but retirement taxation can become surprisingly layered.
Most retirees start by looking at their current marginal tax bracket. If a conversion keeps you within the same bracket, the analysis may be relatively straightforward. But large conversions can push portions of income into higher brackets, which is why many retirees choose to convert incrementally over several years rather than all at once.
A gradual strategy often allows you to “fill up” a particular tax bracket each year without spilling into the next one.
Why Social Security Taxation Matters
One complication is that Roth conversions can indirectly increase the taxation of Social Security benefits.
Depending on your total income, anywhere from 0% to 85% of your Social Security benefits may become taxable. Additional income from a Roth conversion can cause a larger percentage of those benefits to be included in taxable income.
That means the true tax cost of a conversion may be higher than it initially appears.
This is one reason retirees sometimes underestimate the impact of conversions. It’s not just the tax on the converted dollars themselves. The conversion can also trigger taxation elsewhere in the return.
Medicare Premiums Can Also Be Affected
Higher income can create another issue: increased Medicare premiums.
Medicare Parts B and D use income-based surcharges known as IRMAA (Income-Related Monthly Adjustment Amounts). Roth conversions increase modified adjusted gross income, which can push retirees into higher premium tiers.
Crossing an IRMAA threshold does not automatically mean a conversion is a bad idea. It simply means the added premium cost should be part of the analysis.
Sometimes paying somewhat higher premiums now still produces meaningful long-term tax savings later.
Future RMDs Often Become More Aggressive
Another factor many retirees overlook is that RMD percentages increase with age.
Early RMDs may only represent around 4% of the account balance, but the required percentage gradually rises over time. By advanced ages, mandatory distributions can become quite large relative to the remaining balance.
If IRA balances continue growing and withdrawals remain relatively modest, future RMDs can eventually create unexpectedly high taxable income later in retirement.
That can impact tax brackets, Social Security taxation and Medicare premiums all at once.
For some retirees, Roth conversions are less about reducing taxes immediately and more about preventing larger tax problems years down the road.
Why Many Retirees Prefer Partial Conversions
For most people, gradual conversions tend to provide more flexibility than converting a large amount all at once.
Incremental conversions allow you to reassess the strategy each year based on:
- Investment performance
- Changes in tax law
- Spending needs
- Social Security timing
- Medicare considerations
- Changes in income sources
This approach also helps avoid unintentionally creating a large one-year tax spike.
In many cases, retirees target a specific income ceiling each year and convert only enough to stay below it.
Should You Do Roth Conversions After RMDs Begin?
Even after RMDs begin, Roth conversions can still be an effective planning tool. They may help reduce future required distributions, create more flexibility in retirement income planning and potentially lower long-term taxes.
The challenge is that the analysis involves much more than simply comparing tax brackets. Social Security taxation, Medicare premiums, future RMD growth and the timing of conversions all matter.
For many retirees, a measured multi-year conversion strategy ends up being the most efficient path, but the right answer depends heavily on your overall retirement plan and projected future income.
