Is Roth Conversion Good for Medicare Planning?

Table of Contents

• What Is a Roth Conversion and Why Medicare Planning Matters
• Understanding IRMAA and the Two-Year Lookback Period
• Roth Conversion Tax Implications for Retirees
• How to Avoid Medicare IRMAA Surcharges Through Strategic Planning
• Medicare Part B Premium Brackets and Conversion Strategy
• Pros and Cons of Roth Conversions for Medicare Planning
• When Roth Conversions Don't Make Sense
• Conclusion

Last Updated: August 25, 2026

What Is a Roth Conversion and Why Medicare Planning Matters

A Roth conversion moves money from a traditional, tax-deferred retirement account like a traditional IRA or 401(k) into a Roth IRA, where funds grow tax-free. You pay income taxes on the converted amount in that tax year, but all future growth and withdrawals remain tax-free. This strategy is central to retirement planning, particularly for those approaching Medicare eligibility.

The critical issue: your retirement income directly determines how much you'll pay for Medicare premiums. The higher your Modified Adjusted Gross Income (MAGI), the more you'll pay for Medicare Part B and Part D coverage through Income-Related Monthly Adjustment Amount (IRMAA) surcharges (cms.gov). A poorly timed Roth conversion can trigger years of premium increases that offset long-term tax savings. Conversely, a strategic conversion executed at the right time can reduce your lifetime tax burden while keeping Medicare costs manageable.

Understanding whether a Roth conversion makes sense requires examining three interconnected variables: your current tax bracket, your projected Medicare income thresholds, and your time horizon until you claim Social Security and enroll in Medicare.

Understanding IRMAA and the Two-Year Lookback Period

Income-Related Monthly Adjustment Amount (IRMAA) is Medicare's mechanism for charging higher premiums to higher-income beneficiaries. When your MAGI exceeds certain thresholds, you pay surcharges on top of standard Medicare Part B and Part D premiums.

Here's the critical timing issue: Medicare uses a two-year lookback period to determine your income (ssa.gov). If you take a Roth conversion in 2026, Medicare will examine your 2024 tax return to calculate your 2026 IRMAA surcharges. A large conversion can spike your income in a single year, triggering IRMAA surcharges two years later, even if your income drops significantly afterward. You're locked into higher premiums for that two-year period based on a one-time event.

If you're not yet on Medicare, you have flexibility to execute conversions without immediate IRMAA consequences. Once enrolled, the two-year lag means you need to plan conversions carefully to avoid triggering surcharges that persist for years.

Roth Conversion Tax Implications for Retirees

When you execute a Roth conversion, the converted amount is treated as ordinary income, adding directly to your taxable income for that tax year. If you convert $100,000 from a traditional IRA to a Roth, you'll owe federal income tax on that $100,000 in the year of conversion.

This tax bill is immediate and significant. You need sufficient liquid assets outside your retirement accounts to cover the tax bill. If you use funds from the conversion itself to pay taxes, you reduce the amount that actually gets converted to the Roth.

The tax rate depends on your marginal tax bracket in the conversion year. If you're in the 22% bracket, converting $100,000 costs you $22,000 in federal taxes. State income taxes add another layer, South Carolina has a graduated state individual income tax, with a top rate of 6% for 2025, and a top rate of 5.21% for 2026 (dor.sc.gov). The total tax bill could easily exceed $25,000 when you factor in both federal and state taxes.

The strategic question: is paying $25,000 in taxes today worth the benefit of having $100,000 growing tax-free for the next 20 or 30 years? For many retirees, yes, but only if the conversion doesn't trigger IRMAA surcharges that consume much of the long-term savings.

How to Avoid Medicare IRMAA Surcharges Through Strategic Planning

The core strategy is timing your Roth conversions to keep your MAGI below the surcharge thresholds during the years Medicare will examine. This requires working backward from your Medicare enrollment date and identifying years when you have the most flexibility to execute conversions without triggering surcharges.

The most effective approach involves executing conversions during the years before you claim Social Security. If you plan to claim at age 70 but will enroll in Medicare at age 65, you have a five-year window where your income is lower than it will be once Social Security begins. During those years, you can convert larger amounts without triggering IRMAA surcharges.

A second strategy involves spreading conversions across multiple years rather than executing one large conversion. Converting $100,000 per year over five years allows you to stay below surcharge thresholds in most years, assuming your other income remains stable.

A third strategy involves managing other income sources strategically. If you have flexibility to defer capital gains, delay bonuses, or time asset sales, you can coordinate these decisions with your Roth conversion strategy. Executing a conversion in a year when you have minimal other income is far less expensive than converting in a year when you have realized capital gains.

All these strategies require clarity about your future income, which depends on decisions you haven't yet made. Working with a financial advisor who specializes in retirement tax planning is valuable. An advisor can model multiple scenarios and help you identify the conversion strategy that minimizes your total tax and Medicare costs over your lifetime.

Medicare Part B Premium Brackets and Conversion Strategy

Medicare Part B premiums are structured in tiers based on MAGI. The higher your income, the more you pay. IRMAA surcharges create "income cliffs", once your MAGI crosses a threshold, you jump to the next surcharge tier. Earning an additional $1 of income could trigger $100 or more in annual Medicare surcharges.

If a threshold is at $100,000 of MAGI and your projected income without a conversion is $98,000, converting $5,000 might seem safe. But if the conversion pushes your MAGI to $103,000, you've crossed the threshold and triggered surcharges. The additional $3,000 of income above the threshold costs you far more in Medicare premiums than the $3,000 itself.

Strategic planning involves identifying these thresholds and determining whether a conversion pushes you over one. If a conversion will trigger surcharges, you need to evaluate whether the long-term tax savings from the Roth outweigh the near-term surcharge costs.

Financial planning tools like Income Lab's Tax Lab software model these interactions directly, showing you not just the immediate tax cost of a conversion but also the Medicare surcharge impact two years later.

Note: These are approximate percentages. Actual surcharge amounts are adjusted annually and vary by year of enrollment.

Pros and Cons of Roth Conversions for Medicare Planning

The case for Roth conversions in retirement:

Tax-free growth is the fundamental benefit. A $100,000 conversion that grows at 5% annually becomes $265,000 tax-free over 20 years, a savings of roughly $65,000 in taxes compared to keeping the money in a traditional IRA.

Roth conversions solve the required minimum distribution (RMD) problem. Traditional IRAs force you to take RMDs starting at age 73, which increases your taxable income and potentially triggers IRMAA surcharges. A Roth IRA has no RMDs during your lifetime, giving you complete control over withdrawals.

Estate planning benefits are significant. When you leave a traditional IRA to heirs, they inherit both the assets and the tax liability. A Roth IRA passes to heirs tax-free, meaningfully increasing the after-tax value of your estate.

Tax bracket management is another advantage. If you're in a lower tax bracket during early retirement but expect to be in a higher bracket later, converting during the lower-bracket years locks in a lower tax rate.

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The case against Roth conversions:

The immediate tax cost is the most obvious drawback. Paying $25,000 in taxes today requires having sufficient liquid assets outside your retirement accounts to cover the bill without disrupting retirement spending.

IRMAA surcharges can erase much of the long-term benefit. If a conversion triggers two years of Medicare surcharges that cost $10,000, the net benefit shrinks significantly.

Roth conversions have a "break-even" timeline. If you convert at age 65 and die at age 75, you've had only 10 years of tax-free growth. The long-term benefit is much larger if you live into your 90s.

State tax considerations matter as well. South Carolina's income tax applies to conversions. If you eventually move to a state with no income tax, converting before the move locks in South Carolina's tax rate.

When Roth Conversions Don't Make Sense

If you're still working and in a high tax bracket, a conversion during your working years is almost always expensive. Waiting until you retire and your income drops is far more efficient.

If you have substantial traditional IRA assets and limited liquid savings outside retirement accounts, a large conversion may be impractical. You need cash to pay the conversion tax bill.

If you're within a few years of claiming Social Security, a conversion may not have enough time to generate meaningful tax-free growth.

If you have a Qualified Charitable Distribution strategy, where you donate directly from your IRA to charity after age 73, a Roth conversion may conflict with that plan.

Conclusion

Is a Roth conversion good for Medicare planning? The answer is context-dependent. For retirees who can afford the immediate tax cost, who have sufficient time for tax-free growth, and who can execute conversions without triggering IRMAA surcharges, Roth conversions are often excellent. They reduce lifetime tax liability, provide withdrawal flexibility, and maximize what you can pass to heirs.

For retirees already in high tax brackets, with limited liquid assets, or very close to Medicare enrollment, conversions may be counterproductive. The immediate tax cost and surcharge risk can outweigh long-term benefits.

The critical mistake most retirees make is evaluating Roth conversions in isolation from Medicare planning. A conversion that looks great from a tax perspective can become expensive once IRMAA surcharges are factored in. Conversely, a seemingly modest conversion executed at the right time can save tens of thousands of dollars over your lifetime.

Tax-Free Me specializes in exactly this kind of integrated planning. Working with a financial advisor who understands both tax strategy and Medicare cost management helps you avoid costly mistakes and identify conversions that actually improve your retirement outcome. If you're considering a Roth conversion, getting a professional analysis of how it affects your specific Medicare situation is one of the most valuable investments you can make.

=== FAQ ANSWERS (audit these too, same rules) ===

[1] Q: How does a Roth conversion impact my Medicare Part B and Part D premiums? A: A Roth conversion increases your Modified Adjusted Gross Income (MAGI) in the year you convert, which can trigger Income-Related Monthly Adjustment Amount (IRMAA) surcharges on Medicare Part B and Part D premiums. The IRS uses a two-year lookback period, meaning your 2024 income determines your 2026 premiums. A large conversion in one year could push you into a higher premium bracket for the following two years, even if your income normalizes later. Strategic timing and amount control can minimize this impact.

[2] Q: What is the biggest mistake people make with Roth conversions and Medicare planning? A: The most common mistake is converting too much in a single year without considering the IRMAA lookback period. Retirees often focus only on immediate tax savings and overlook how the increased income will affect Medicare premiums for the next two years. Another critical error is failing to coordinate Roth conversions with Social Security claiming strategy, converting large amounts while claiming Social Security early can compound IRMAA surcharges. Working with a financial advisor to model multi-year scenarios helps avoid these costly mistakes.

[3] Q: Can I appeal an IRMAA determination if a Roth conversion pushed me into a higher bracket? A: Yes, you can appeal an IRMAA determination if you experience a life-changing event (such as retirement, divorce, or death of a spouse) that significantly reduces your income. The Social Security Administration allows you to request a recalculation using your current year's income instead of the two-year lookback period. You must file Form SSA-44 with supporting documentation. However, a Roth conversion itself is not considered a life-changing event, so standard conversions typically cannot be appealed. Planning conversions carefully to stay below IRMAA thresholds is more effective than relying on appeals.

[4] Q: At what age should I stop doing Roth conversions to avoid Medicare surcharges? A: There is no specific age cutoff, but the calculus changes as you approach and enter Medicare eligibility at age 65. Before Medicare, Roth conversions are generally lower risk since IRMAA surcharges don't apply. Once you enroll in Medicare, every conversion dollar triggers the two-year lookback, making surcharges a real concern. Many retirees continue conversions into their 70s and beyond if they can keep income below IRMAA thresholds. The key is modeling your specific situation, your Social Security start date, Required Minimum Distributions (RMDs), and healthcare costs, to determine whether conversions still make sense at your age.

[5] Q: What strategies actually work to minimize IRMAA impact when doing a Roth conversion? A: Effective strategies include spreading conversions over multiple years to stay below IRMAA thresholds, timing conversions before you claim Social Security, coordinating with tax-deferred withdrawals to manage total income, and using tax-loss harvesting in taxable accounts to offset conversion gains. Some retirees delay large conversions until after they reach age 73 and can use Qualified Charitable Distributions (QCDs) to reduce Required Minimum Distributions. Advanced planning tools and professional guidance help identify the optimal conversion amount for your specific income level and Medicare bracket. Each situation is unique, so personalized analysis beats generic rules.

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