The right amount to convert usually comes down to your current taxable income and how much room you have left in your target tax bracket. The goal is to convert enough to improve your tax flexibility in retirement without creating an unnecessary tax problem today.
There is no universal dollar amount that works for everyone. But there is a repeatable process. You estimate your income for the year, choose a bracket target, calculate how much space is left in that bracket, and then decide how much of that space you want to fill with a conversion.
Most people who do this well do not convert everything at once. They spread conversions over several years, converting a measured amount each year. Over time, that strategy can meaningfully reduce future required minimum distributions (RMDs), lower lifetime taxes, and give you more flexibility when it comes time to actually spend your money in retirement.
Key Takeaways
- Treat your tax bracket like a limit. Fill it, don’t exceed it.
- Conversions increase income and can trigger Medicare IRMAA (two-year lookback).
- The amount converted is taxed as ordinary income.
- Timing matters. Market dips can lower the tax cost.
- Large conversions can reduce or eliminate deductions.
Step 1: Estimate This Year's Taxable Income
Before you can figure out how much to convert, you need a reasonably accurate picture of what your taxable income will be for the year.
This does not have to be perfect. You are working with a projection, not a tax return. But the closer you are, the better your conversion decision will be. That is also why many advisors recommend waiting until later in the year to execute the conversion itself, since by then you have a clearer picture of what your total income will actually look like.
Income Sources to Account For
Add up the income you expect from every major source:
- Wages, salary, or self-employment income
- Social Security benefits (note: up to 85% may be taxable depending on your total income)
- Pension or annuity income
- Required minimum distributions from traditional IRAs or 401(k)s, if applicable
- Dividends, interest, and capital gain distributions from investment accounts
- Rental income or any other recurring income streams
If you are retired and not yet taking RMDs or Social Security, your projected income may actually be quite low. That gap period, often between retirement and age 73, is one of the best windows for Roth conversions.
Deductions Basics
Once you know your gross income, subtract your deductions to arrive at taxable income. Most people in retirement take the standard deduction, which in 2025 is $15,000 for single filers and $30,000 for married couples filing jointly. If you itemize, use your expected deductible expenses instead.
The number you land on after deductions is your taxable income baseline. That is the starting point for your bracket math.
Step 2: Choose a Target Bracket
Once you know approximately where your taxable income will land, you can look at which bracket you are in and decide how much of it you want to fill.
Why the "Lowest Bracket" Is Not Always the Answer
A common instinct is to stay in the lowest possible bracket. That may make sense in some situations, but not always.
When determining how much to convert, many planners target an amount that fills up a specific tax bracket. For example, if your income lands at $140,000 for the year and you file jointly, you have room to convert up to the top of the 22% bracket by calculating the difference between your income and the bracket ceiling.
The decision of whether to fill the 22% bracket, push into the 24% bracket, or stop earlier depends on your personal situation, including how much pre-tax money you have, how many years you plan to convert, and what you expect your retirement income picture to look like once Social Security and RMDs are both active.
Because of how the tax code is structured, there are often “add-on” effects created by adding income that are not accounted for when simply looking at a tax bracket. Your true marginal tax rate on a Roth conversion may be higher or lower than your stated bracket depending on how the conversion interacts with Social Security taxation, Medicare premiums, or other income-related thresholds.
Planning for Future RMDs and Income
One of the most compelling reasons to convert is to reduce the size of future RMDs. RMDs start at age 73 for most people (age 75 for those born in 1960 or later) and are calculated as a percentage of your traditional IRA and 401(k) balances. Roth IRAs have no RMD requirements. When you convert pre-tax money into a Roth, you reduce the balance that will eventually be subject to mandatory distributions, potentially lowering your tax burden well into your 70s and 80s.
Think about what your income will look like when both Social Security and RMDs are running at the same time. If that combined income pushes you into a higher bracket, you may want to do more converting now, even if it means paying a bit more in taxes today.
A conversion ladder is a multi-year approach where you convert just enough each year to fill a target bracket, typically 22% or 24%, without spilling into the next one. The goal is to spread a large pre-tax balance across several years at a lower rate rather than converting everything at once and triggering much higher rates.
Step 3: Calculate a Conversion Range
With your taxable income estimate and your target bracket in mind, the math is straightforward.
Take the top of your target bracket and subtract your estimated taxable income. That difference is your maximum conversion room in that bracket.
For example, if you are married filing jointly and expect $150,000 in taxable income for the year, and you want to stay within the 22% bracket (which runs to $206,700 in 2025), you could convert up to approximately $56,700 without moving into the 24% bracket. That calculation, bracket ceiling minus projected income, gives you the dollar amount you can safely convert within your target range.
This is a ceiling, not a recommendation. You may decide to convert the full amount, a portion of it, or nothing at all based on your cash flow situation and tax payment plan.
How to Leave a Buffer
Do not aim to convert right up to the edge of a bracket. Give yourself a cushion, usually $2,000 to $5,000 below the ceiling. Income projections are not perfectly accurate, and an unexpected dividend, interest payment, or year-end distribution could push you over the line without warning.
This is especially important if you are managing IRMAA thresholds. Even a small amount of additional income can push you into the next Medicare premium tier and trigger significantly higher costs, so leaving room for surprises is good planning practice.
What to Do If Income Changes Mid-Year
Life does not always follow the plan. A part-time consulting gig, an unexpected capital gain from a fund distribution, or a bonus you did not anticipate can shift your income picture mid-year.
If your income looks higher than expected, you can reduce or delay the conversion. If income comes in lower, you may have more room than you thought. That is another reason to wait until you have a clear year-end income picture before executing the conversion, particularly if your income varies year to year.
If your income in a particular year is lower than normal, that can be a good opportunity for a larger conversion. Conversely, a high-income year often means it is better to convert less or skip the conversion entirely.
Step 4: Plan How Taxes Will Be Paid
This step is one most people overlook, and it matters more than it might seem. How you pay the tax bill on a Roth conversion affects both the immediate cost and the long-term benefit.
Paying From Cash vs. Withholding
There are two ways to cover the taxes on a Roth conversion: you can pay from outside funds, like cash in a savings account or a taxable brokerage account, or you can have taxes withheld from the conversion amount itself.
Paying from outside funds is almost always the better approach. Here is why: when you withhold taxes from the conversion, that withheld portion never makes it into the Roth account. It does not grow tax-free. You are effectively converting less while also losing the compounding benefit on the withheld dollars.
Paying taxes from other taxable assets, such as cash from a bank account, allows you to maximize the amount that converts to tax-free status. You are essentially exchanging taxable assets for tax-free Roth assets, which is a favorable trade when done at a low enough rate.
If you are under age 59 1/2, the IRS treats withheld taxes as a premature distribution, meaning taxes withheld are also subject to an additional 10% penalty. That makes paying from outside funds even more important for younger converters.
Estimated Tax Planning
When you do a Roth conversion, your taxes are not due at the moment of conversion. The converted amount is added to your taxable income for that calendar year, and taxes are due by April 15 of the following year. However, you may need to make estimated payments throughout the year to avoid underpayment penalties.
If you had significant income in the prior year, you may be able to avoid underpayment penalties by simply making sure your total tax payments for the year equal or exceed your prior year’s tax bill, which the IRS calls the safe harbor rule. If your prior year adjusted gross income exceeded $150,000, the safe harbor is 110% of your prior year’s tax liability, which creates predictability regardless of how large your current year conversion is.
If you prefer to match current-year income, you can make quarterly estimated payments using IRS Form 1040-ES. A tax professional or financial advisor can help you determine which approach makes more sense given your specific situation.
FAQs
There is no single dollar amount that works for everyone. The most commonly used rule of thumb is to convert enough to fill your current tax bracket without crossing into the next one. A married couple in the 22% bracket with $150,000 in projected taxable income might convert $50,000 to $55,000 to fill that bracket. But the right amount depends on your total pre-tax balance, expected retirement income, years until RMDs begin, and whether you have outside cash to pay the tax. Think of the bracket ceiling as a ceiling, not a target.
Most advisors suggest executing conversions toward the end of the year, typically October through December. By then, you have a much clearer picture of your total taxable income for the year, which helps you avoid accidental bracket spikes. That said, if your income is very predictable, you can convert earlier. Just be careful about year-end fund distributions from mutual funds or unexpected events that could shift your income picture.
Yes. There is no limit on the number of conversions you can do in a single year. You can convert multiple times, in varying amounts, across multiple IRA accounts. The total amount converted for the year is what gets added to your taxable income, and that is what determines your tax. Spreading smaller conversions across the year can help if your income is irregular or if you want to match conversions to specific cash flow opportunities.
Yes. Every dollar you convert from a traditional IRA or 401(k) is a dollar that will no longer be subject to RMD calculations at age 73. Over time, a consistent multi-year conversion strategy can significantly shrink your future RMDs. That matters because large RMDs can push you into a higher bracket late in retirement, increase the taxable portion of your Social Security benefits, and trigger higher Medicare premiums. Converting earlier, even at a modest tax cost now, can reduce all of those future pressures.
A market downturn can actually be a favorable time to convert. When account values are lower, you pay taxes on a smaller amount to move the same number of shares into the Roth. If and when the market recovers, that growth happens inside the Roth account and is not taxed. A market decline means you might move less cash into the Roth account, which reduces the immediate tax impact while still getting the shares repositioned into tax-free status before they recover. This is not a reason to time the market, but if a conversion was already part of your plan and values are lower, executing it during that period tends to be more efficient.
Yes, this is one of the most frequently overlooked costs in conversion planning. A Roth conversion increases your modified adjusted gross income in the year it is executed. That added income can push you into a higher IRMAA tier, which increases your Medicare Part B and Part D premiums. The catch is that Medicare premium surcharges are based on your income from two years prior, so a conversion done in 2025 could affect your premiums in 2027. Even a moderate-sized conversion for a couple with $200,000 in existing income could trigger IRMAA surcharges adding thousands of dollars in Medicare costs over two years. Always check IRMAA thresholds before finalizing your conversion amount.
State tax treatment varies significantly. Nevada has no state income tax, which makes Roth conversions more straightforward for Las Vegas-area residents since there is no additional state-level cost to account for. In states with income tax, the conversion amount is typically taxed as ordinary income at the state rate as well, which increases the true cost of converting. If you live in a high-tax state or are considering relocating in retirement to a no-income-tax state, that timing could affect your conversion strategy. Converting before a move to a lower-tax state is generally less efficient than waiting until after you have established residency.
You will need last year's tax return to review your adjusted gross income and prior year tax liability, current account statements for all traditional IRAs and pre-tax retirement accounts, a year-to-date income summary to project this year's taxable income, and information on any Social Security benefits, pension income, or RMDs already scheduled for the year. If you work with a financial advisor or CPA, having these documents ready before your planning meeting will save time and help you model conversion scenarios with accurate inputs.
Build a Roth Conversion Plan That Fits Your Bracket
Choosing how much to convert each year comes down to staying within the right limits, your tax bracket, Medicare thresholds, and any deductions you want to preserve. A clear plan can help you use those ranges intentionally instead of crossing them by accident. If you’d like help mapping out your conversion range and timing, schedule a complimentary consultation with one of our CFP® professionals at Bauman Wealth Advisors. We’ll help you size each conversion so it supports your long-term plan without creating unnecessary tax or Medicare surprises.
