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Roth Conversions & IRMAA Timing in Grand Junction 2026

A Roth conversion is a smart retirement move for a lot of higher earners — but it counts as income, and Medicare quietly prices your premium off the income you reported two years ago. Here's how the timing works in 2026.

Medicare On Main Data Desk

Published July 28, 2026 · 8 min read · Reviewed by Brian Penner

Converting a traditional IRA to a Roth can be one of the best moves a higher-income retiree makes — and it can also, quietly, raise your Medicare premium two years later. The two are connected by a single number: your modified adjusted gross income. A conversion adds to it, and Medicare's income-related surcharge is calculated from it — on a two-year delay that catches people off guard. None of this means "don't convert." It means convert on purpose, with the Medicare calendar in view. Here's how the timing works in 2026.

How does a Roth conversion connect to my Medicare premium?

Two rules meet here. First, when you convert money from a traditional IRA or 401(k) to a Roth, the IRS treats the converted amount as ordinary income in that year (you report it on Form 8606). That's the price of admission for tax-free growth and tax-free withdrawals later. Second, Medicare charges higher-income beneficiaries an extra amount — the Income-Related Monthly Adjustment Amount (IRMAA) — on top of the standard Part B and Part D premiums, and it decides who pays by looking at your MAGI (your adjusted gross income plus any tax-exempt interest).

So a conversion that's great for your long-term tax picture can, in the year you do it, push your MAGI up a tier or two — and that tier follows you to your Medicare premium two years down the road. The standard 2026 Part B premium is $202.90 a month with a $283 deductible; above the thresholds, a surcharge is added to both Part B and Part D. It's a one-year effect for a one-year conversion, but if you convert several years in a row, you can stack several years of surcharges.

What is the two-year IRMAA lookback?

Social Security doesn't know your current income — it uses the most recent tax return the IRS has passed along, which is generally from two years earlier. That means:

Source: SSA — Medicare premiums: Rules for higher-income beneficiaries · CMS: 2026 Medicare Parts A & B Premiums and Deductibles.

The lookback cuts both ways. A high-income year raises your premium two years later — but because it's a single year, the surcharge drops back off once a lower-income return works its way through. That's the mechanism serious conversion planning works around: concentrate the taxable income into years you choose, and keep the years that will set your Medicare premiums as clean as you can.

The 2026 IRMAA thresholds

Here are the 2026 income-related tiers. The MAGI figures are your 2024 numbers (single or joint); the surcharge is added to your Part B premium, and a separate Part D surcharge stacks on top:

Thresholds and standard premium per CMS (2026 Parts A & B) and SSA. Per-tier Part B amounts are rounded to the nearest dollar; CMS sets the exact figure each year.

Notice how close together the lower tiers sit. For a joint filer, the difference between staying under $218,000 and landing in Tier 1 is one dollar of MAGI — and that dollar can cost roughly $80 a month more in Part B, about $975 for the year, per person, plus the Part D surcharge. A conversion sized without that line in mind can cost far more than the tax on the conversion alone.

Why you usually can't appeal a conversion away

This is the part that surprises people, and it's the reason timing beats hoping. You can ask Social Security to lower your IRMAA with Form SSA-44 — but only after a qualifying life-changing event. The list is specific:

• Marriage, divorce or annulment, or the death of a spouse
• Work stoppage or a reduction in work hours
• Loss of income-producing property (outside of a sale you chose)
• Loss or reduction of pension income
• An employer settlement payment

A voluntary Roth conversion isn't on that list — and neither is a capital gain from selling a home, land, or investments. Social Security only recognizes involuntary events that reduce your income; income you chose to realize doesn't qualify. So if a conversion pushes you over a threshold, the surcharge generally stands for that year. The lesson isn't to avoid conversions — it's to size and time them before you pull the trigger, because there's no do-over form for a conversion you decided to make.

Timing conversions around 63–65

Every situation is different, and the actual math belongs with your tax advisor — but here's the shape of it that keeps Medicare in the picture:

1. Map your low-income years. The stretch after you stop working and before Social Security, required minimum distributions, and Medicare all kick in is often when your MAGI is naturally lowest — frequently the early-to-mid 60s. Those are the years many retirees fill with conversions.
2. Watch the 63-and-64 returns. Because of the two-year lookback, your income at 63 sets your first Medicare premium at 65, and 64 sets 66. A large conversion in those two years can greet you with an IRMAA surcharge the moment you enroll.
3. Size each conversion to a threshold, not just a tax bracket. The gap to the next IRMAA line ($109,000 single / $218,000 joint, and the tiers above) is its own ceiling to respect, separate from the income-tax brackets.
4. Remember the payoff. Qualified Roth withdrawals later don't count in MAGI, so front-loading the tax in controlled years can mean fewer IRMAA surprises once RMDs begin. Weigh the bump now against the smoother years later.
5. Coordinate the two calendars. Your tax advisor runs the conversion math; we help you see how it lands on your Medicare premiums. The two conversations are better had together than apart.

Why does this hit higher earners in Mesa County?

Grand Junction and the wider Western Slope have their share of retirees with real assets to manage — business owners who sold, professionals with strong 401(k)s and IRAs, and landowners whose property has appreciated. Those are exactly the households where a Roth conversion, a business-sale year, or a capital gain can swing MAGI across an IRMAA line. Coordinating that income with the Medicare calendar is the whole game. And whatever you decide on the tax side, the plan that fits your health matters just as much — so here's the local chronic-condition picture that should also shape your Part D and Advantage choices:

Chronic-condition rates among Mesa County adults

Source: CDC PLACES, 2023 — via the Medicare On Main Data Desk. Model-based prevalence among Mesa County adults, 2023.

One more 2026 number worth knowing while you plan: your out-of-pocket costs for covered Part D drugs are capped at $2,100 for the year, so if you manage any of the conditions above, the plan's formulary — not just its premium — is where the real money is. Match coverage to your medications, and match your income timing to the IRMAA calendar.

How we know all this: the Medicare On Main Data Desk builds every article on public data — here, the 2026 Part B premium and deductible from CMS.gov, the IRMAA thresholds and two-year-lookback rule from SSA, the taxability of Roth conversions from the IRS, the SSA-44 life-changing-event list from Social Security, and Mesa County health figures from CDC PLACES (2023). This is education, not advice; Roth-conversion and IRMAA tax questions belong with your tax professional, and you should confirm your plan, costs, and eligibility with a licensed agent or Medicare.gov. We take no payment from any carrier to feature a plan.