How to Use Roth Conversions to Slash Your Retirement Tax Bill

Here's a retirement planning secret that could save you $50,000 or more in lifetime taxes — and most people have never heard of it.

If you've spent decades diligently contributing to a traditional 401(k) or IRA, you've built an impressive nest egg. But there's a catch: every dollar you withdraw in retirement will be taxed as ordinary income. Combine that with Social Security benefits, Required Minimum Distributions (RMDs), and potential IRMAA surcharges on Medicare, and your tax bill in retirement might be far larger than you expect.

The solution? A strategic Roth conversion plan. By systematically moving money from your traditional retirement accounts into a Roth IRA during the right years, you can dramatically reduce your lifetime tax burden, eliminate RMDs on converted funds, and leave your heirs tax-free money.

This guide walks you through exactly how Roth conversions work, when they make the most sense, and how to build a year-by-year conversion strategy for 2026 and beyond.

What Is a Roth Conversion and Why Should You Care?

A Roth conversion is simply the process of moving money from a traditional IRA or 401(k) into a Roth IRA. You pay income tax on the amount you convert in the year you do it, but from that point forward, the money grows tax-free and comes out tax-free in retirement.

Think of it like paying the toll upfront to drive on a highway with no speed limits and no future tolls — ever.

The Core Tax Advantage

With a traditional IRA, you got a tax deduction when you contributed, but you'll pay taxes on every withdrawal. With a Roth IRA, there's no upfront deduction, but qualified withdrawals are completely tax-free.

Here's why conversions are so powerful: if you can move money from a traditional account to a Roth account during years when your tax rate is low, you lock in that low rate forever. The money then grows and is withdrawn at a 0% tax rate.

For 2026, the federal income tax brackets for a married couple filing jointly look like this:

• 10% on income up to $23,850
• 12% on income from $23,851 to $97,000
• 22% on income from $97,001 to $206,700
• 24% on income from $206,701 to $394,600
• 32% on income from $394,601 to $501,050
• 35% on income from $501,051 to $751,600
• 37% on income over $751,600

The goal is to "fill up" the lower brackets with Roth conversions during years when your income is naturally low — before Social Security kicks in, before RMDs start, or during early retirement.

The Golden Window: When Roth Conversions Work Best

Not every year is created equal for Roth conversions. There are specific life stages where the strategy delivers the biggest bang for your buck.

The Gap Years Between Retirement and Age 73

If you retire at 62 but delay Social Security until 67 or 70, you may have several years with very little taxable income. These "gap years" are pure gold for Roth conversions.

Example: Mark and Lisa, both 63, retired last year. They're living off savings and a small pension of $30,000 per year. Their taxable income is just $30,000. As a married couple, they could convert roughly $67,000 and stay entirely within the 12% federal tax bracket. That's a tax bill of about $8,040 on the conversion — money that would have been taxed at 22% or higher if withdrawn later during RMDs.

Over five gap years, Mark and Lisa could convert $335,000 at the 12% rate, saving approximately $33,500 compared to paying the 22% rate later.

Years With Unusual Deductions or Losses

Had a year with large medical expenses, significant charitable donations, or a business loss? Your taxable income drops, creating room for tax-efficient conversions. Always look for these opportunistic windows.

Before RMDs Force Your Hand

Starting in 2026, Required Minimum Distributions begin at age 73 (and will move to 75 in 2033 under SECURE 2.0). Once RMDs kick in, they push your income higher automatically, leaving less room for low-bracket conversions. The years before RMDs start are your best conversion window.

How to Build a Roth Conversion Strategy Step by Step

A successful Roth conversion strategy isn't about converting everything at once. It's about converting the right amount each year to stay in a target tax bracket. Here's how to do it.

Step 1: Calculate Your "Baseline" Taxable Income

Add up all your income sources for the year excluding any conversion:

• Pension income
• Social Security benefits (up to 85% may be taxable)
• Part-time work or consulting income
• Interest, dividends, and capital gains
• Rental income

Subtract your standard deduction ($32,300 for married filing jointly in 2026) or itemized deductions. The result is your baseline taxable income.

Step 2: Choose Your Target Tax Bracket

Decide how much tax you're willing to pay. Most financial planners recommend filling up to the top of the 22% or 24% bracket, depending on your situation.

For a married couple with $40,000 in baseline taxable income, converting up to $166,700 would keep you within the 22% bracket ($206,700 bracket ceiling minus $40,000). That's a substantial conversion at a historically favorable rate.

Step 3: Run the Numbers on Future Savings

Before converting, estimate what your tax rate would be if you left the money in the traditional account and withdrew it later. Consider:

• RMDs increasing your income each year after 73
• Social Security benefits becoming more taxable
• Potential IRMAA surcharges adding $1,000 to $5,000+ per year to Medicare premiums
• State income taxes in your retirement state
• Possible future tax rate increases

If your current conversion rate is lower than your projected future withdrawal rate, the conversion is a win.

Step 4: Execute the Conversion

Contact your brokerage or IRA custodian to initiate the conversion. Most major brokerages — Fidelity, Vanguard, Schwab — make this a straightforward online process. The money moves from your traditional IRA to your Roth IRA, and you'll receive a 1099-R at tax time.

Critical rule: Pay the taxes from outside the converted funds. If you use IRA money to cover the tax bill, you reduce the amount that gets the tax-free Roth treatment, and if you're under 59½, you may owe a 10% penalty on the amount used for taxes.

Step 5: Repeat Annually and Adjust

Review your conversion strategy every year. Tax brackets, income sources, and life circumstances change. The best Roth conversion plans are flexible and recalculated annually.

The Hidden Benefits Most People Overlook

The direct tax savings are compelling, but Roth conversions deliver several additional advantages that can be worth even more over time.

No Required Minimum Distributions

Roth IRAs have no RMDs during the original owner's lifetime. This means your money can continue growing tax-free for as long as you live. If you don't need the money at 73, 80, or even 90, it stays invested and compounding.

For someone with a $500,000 Roth IRA earning 7% annually, skipping RMDs for 10 years means roughly $483,000 in additional tax-free growth compared to being forced to withdraw.

Lower Medicare Premiums

Medicare Part B and Part D premiums are based on your Modified Adjusted Gross Income (MAGI) from two years prior. High income triggers IRMAA surcharges that can add $1,000 to over $5,000 per person per year to your premiums.

Roth IRA withdrawals don't count toward MAGI. By converting now and withdrawing tax-free later, you can keep your MAGI below IRMAA thresholds and save thousands annually on Medicare.

Reduced Social Security Taxation

Up to 85% of your Social Security benefits can be taxed based on your "combined income." Roth withdrawals don't count toward this calculation. Strategic conversions today mean more of your Social Security stays tax-free tomorrow.

Tax-Free Inheritance for Your Heirs

Under the SECURE Act, most non-spouse beneficiaries must empty an inherited IRA within 10 years. If they inherit a traditional IRA, they'll owe income tax on every dollar withdrawn — often at their peak earning years and highest tax rates.

An inherited Roth IRA still must be emptied within 10 years, but every withdrawal is tax-free. Converting now is essentially pre-paying taxes at your lower rate so your children don't have to pay at their higher rate.

Common Roth Conversion Mistakes to Avoid

The strategy is powerful, but there are several pitfalls that can erase the benefits or even cost you money.

Converting Too Much in a Single Year

Converting a massive amount in one year can push you into the 32% or 37% bracket, trigger IRMAA surcharges two years later, and make 85% of your Social Security taxable. Spreading conversions across multiple years at moderate amounts almost always beats a single large conversion.

Forgetting About State Taxes

Federal taxes aren't the whole picture. If you live in a state with income tax, your conversion will be taxed there too. However, if you plan to move to a no-income-tax state like Florida, Texas, or Nevada, consider waiting to convert until after you've established residency.

Ignoring the Two-Year IRMAA Look-Back

Medicare IRMAA surcharges are based on income from two years prior. A large conversion in 2026 could spike your Medicare premiums in 2028. Plan conversion amounts with this two-year lag in mind.

Not Having Cash to Pay the Tax Bill

You need cash outside your retirement accounts to pay the taxes on conversions. If you have to sell investments at a loss or raid your IRA to cover the tax bill, the math may not work in your favor. Before starting a conversion strategy, make sure you have adequate liquid funds earmarked for the tax payments.

Assuming Tax Rates Will Stay the Same

Many provisions of the 2017 Tax Cuts and Jobs Act are set to evolve in coming years. If tax rates increase, conversions done at today's rates look even better. This uncertainty is actually an argument in favor of converting sooner rather than later.

A Real-World Roth Conversion Plan in Action

Let's put it all together with a detailed example.

Meet David and Sarah, both 62, planning to retire this year. Here's their financial picture:

• Combined traditional IRA and 401(k) balances: $1.2 million
• Taxable brokerage account: $300,000
• Expected Social Security at age 70: $4,200/month combined
• Small pension: $24,000/year
• No mortgage

Their conversion plan:

Ages 62-69 (2026-2033): During these eight years before Social Security starts, their only income is the $24,000 pension. After the standard deduction of $32,300, their taxable income is essentially $0. They can convert approximately $97,000 per year and stay within the 12% bracket, paying roughly $9,300 in federal tax per conversion.

Over eight years, they convert $776,000 — nearly two-thirds of their traditional balance — at the 12% bracket. Total tax paid: approximately $74,400.

If they had waited: That same $776,000 withdrawn during RMD years alongside Social Security income would likely be taxed at 22-24%, costing $170,000 to $186,000 in taxes.

Estimated lifetime tax savings: $96,000 to $112,000. And that doesn't include the IRMAA savings, reduced Social Security taxation, or the tax-free inheritance for their children.

Your Next Steps for 2026

Ready to start? Here's your action plan for this year:

1. Gather your numbers. Pull your most recent IRA and 401(k) statements. Know your total traditional retirement account balances.

2. Estimate your 2026 taxable income. Add up all income sources and subtract your deductions to find your baseline.

3. Identify your target bracket. Calculate how much room you have in the 12%, 22%, or 24% bracket.

4. Set aside cash for taxes. Ensure you have liquid funds outside retirement accounts to cover the tax bill — roughly 12-24% of the conversion amount depending on your bracket.

5. Talk to a tax professional. A CPA or tax-focused financial planner can model your specific situation across multiple years and help you avoid the pitfalls described above. The cost of a consultation ($500 to $1,500) is trivial compared to the potential five- or six-figure tax savings.

6. Open a Roth IRA if you don't have one. You can open one at any major brokerage in about 15 minutes.

7. Execute your first conversion before December 31, 2026. Unlike Roth IRA contributions, conversions must be completed within the calendar year. Don't wait until the last week — give yourself time to handle any paperwork.

The Roth conversion strategy isn't glamorous, and it won't make headlines. But for retirees and pre-retirees willing to do the math and act strategically, it's one of the most powerful tax-saving tools available in 2026. The window won't stay open forever — every year you wait is a year of low-bracket conversion space you can never get back.