A cost-of-living adjustment (COLA) is supposed to help your Social Security check keep pace with inflation — but the 2027 COLA may quietly hand a chunk of that raise right back to Medicare and the IRS. Higher monthly benefits can push your income past key thresholds, triggering larger Medicare Part B premiums, income-related surcharges called IRMAA, and a bigger slice of your Social Security being taxed. The good news: if you act before year-end 2026, you can legally reduce the income that determines those costs.

What exactly is COLA, and why does a bigger one hurt?

COLA stands for cost-of-living adjustment. Each October, the Social Security Administration announces the percentage by which all benefits will rise the following January, based on the Consumer Price Index. When inflation is high, the raise looks generous — but “income” as the government measures it doesn’t care whether your extra dollars are just keeping up with rising prices. A larger Social Security check means higher “combined income” (also called provisional income), and that number controls two expensive outcomes: how much of your benefit gets taxed and whether you owe Medicare’s IRMAA surcharges.

How much of Social Security is actually taxable?

Up to 85 percent of your Social Security benefit can be subject to federal income tax — but the exact percentage depends on your combined income, which is your adjusted gross income plus any tax-exempt interest plus half of your annual Social Security benefit. If that combined figure exceeds $34,000 for single filers (or $44,000 for married couples filing jointly), up to 85 percent of benefits are taxable. These thresholds have not been adjusted for inflation since 1994, so even a modest COLA nudges more retirees over the line every year. A 2027 COLA of just 2.5 percent could be enough to tip a borderline household into a higher tax bracket on their benefits.

What is Medicare IRMAA and how does the 2027 COLA trigger it?

IRMAA stands for Income-Related Monthly Adjustment Amount — the extra premium Medicare charges higher-income enrollees on top of the standard Part B and Part D premiums. For 2025, the standard Medicare Part B premium is $185.00 per month. But if your modified adjusted gross income from two years prior exceeds $106,000 (single) or $212,000 (married filing jointly), you pay a surcharge that can add hundreds of dollars per month. Here is the catch everyone misses: Medicare looks at your tax return from two years back. So the income you report in 2025 — including any COLA bump — determines your 2027 Medicare premiums. A seemingly small increase in your 2025 income could push you into the first IRMAA bracket and cost you an extra $800 or more per year, per person.

When should you claim Social Security to maximise your benefit?

Claiming age matters enormously, and the COLA dynamic makes it matter even more. Every month you delay claiming past age 62 increases your eventual benefit by roughly 0.5 to 0.7 percent, and delaying past your full retirement age (currently 67 for most people) earns you an 8 percent annual delayed retirement credit up to age 70. Because COLA increases are applied as a percentage of your base benefit, a larger starting benefit means every future COLA is worth more in real dollars. If you claim early at a reduced benefit, you are essentially compounding a smaller number forever. For people in good health with income from other sources, waiting — even a year or two — can dramatically improve lifetime income and reduce the relative sting of any COLA-driven tax or premium increase.

What are the RMD rules and how do they interact with COLA income?

Required Minimum Distributions (RMDs) are the amounts the IRS forces you to withdraw each year from traditional IRAs, 401(k)s, and most other tax-deferred retirement accounts once you reach age 73 (under current rules through 2032, after which age 75 applies). For 2025 and 2026, those rules remain in effect: if you turned 73 in 2023 or later, your first RMD was due by April 1 of the following year, and every subsequent RMD is due by December 31. The problem is that RMDs count as ordinary income, which stacks on top of Social Security and investment income. A COLA increase piled onto an RMD you were already taking can easily cross the IRMAA or Social Security tax thresholds. Planning your RMD withdrawals strategically — for example, taking them early in the year or pairing them with charitable giving through a Qualified Charitable Distribution — can blunt the impact.

How do you avoid Medicare IRMAA surcharges before 2027?

The most powerful tool available is managing your 2025 modified adjusted gross income before December 31, 2025, since that is the number Medicare will use for 2027 premiums. Practical strategies include: making Qualified Charitable Distributions (QCDs) directly from your IRA to a charity — up to $105,000 per year — which satisfies your RMD without adding to your taxable income; contributing to a Health Savings Account if you are still eligible; harvesting investment losses to offset gains; and doing Roth conversions strategically to reduce future RMDs (and therefore future income). If your income did spike due to a one-time event like a home sale or large conversion, you can appeal your IRMAA determination using IRS Form SSA-44, especially if your income has since dropped due to a life-changing event such as retirement or divorce.

What should you do right now, before the 2027 COLA lands?

First, pull up your 2025 tax picture and estimate your combined income. Compare it to the IRMAA thresholds and the Social Security tax brackets. Second, talk to your tax advisor about whether a Roth conversion, QCD, or tax-loss harvesting move makes sense before year-end. Third, if you have not yet claimed Social Security, revisit your claiming strategy with updated projections — the COLA multiplier effect on a larger base benefit is real money over a 20-year retirement. And fourth, mark your calendar: Medicare premium notices for 2027 will arrive in late 2026, but the income that determines them is being set right now.

A COLA is a raise worth celebrating — as long as you do not let Medicare and the IRS quietly claw most of it back. A little planning today keeps far more of that money where it belongs: in your pocket.

Frequently Asked Questions

Frequently Asked Questions

When should I claim Social Security to maximise my benefit?

Delaying Social Security past your full retirement age (67 for most people born after 1960) earns you an 8 percent annual increase in your benefit up to age 70. Because COLA raises are applied as a percentage of your base benefit, a higher starting amount means every future cost-of-living increase is worth more dollars. For those in good health with other income sources, waiting as long as possible typically produces the highest lifetime payout.

How much of my Social Security benefit is taxable?

Up to 85 percent of your Social Security benefit can be taxed at the federal level, depending on your combined income (adjusted gross income plus tax-exempt interest plus half your Social Security). Single filers with combined income above $34,000 and married filers above $44,000 hit the 85 percent threshold. These limits have not been adjusted for inflation since 1994, so more retirees cross them every year.

What are the RMD rules for 2025 and 2026?

Under current law, required minimum distributions must begin at age 73 for anyone who turned 73 in 2023 or later, with the first RMD due by April 1 of the year after you turn 73 and all subsequent ones by December 31 each year. RMDs are treated as ordinary income and can push your total income over Medicare IRMAA or Social Security tax thresholds. A Qualified Charitable Distribution — donating up to $105,000 directly from your IRA to charity — counts toward your RMD without adding to your taxable income.

How do I avoid Medicare IRMAA surcharges?

IRMAA surcharges are based on your modified adjusted gross income from two years prior, so managing income in the current tax year is the key lever. Strategies include making Qualified Charitable Distributions, harvesting investment losses, timing Roth conversions carefully, and appealing your IRMAA determination (using Form SSA-44) if a one-time income spike — like a home sale — caused the surcharge. For 2025, the single-filer IRMAA threshold starts at $106,000.

What is the Medicare Part B premium for 2025?

The standard Medicare Part B premium for 2025 is $185.00 per month, up from $174.70 in 2024. Higher-income enrollees pay more through IRMAA surcharges, which begin when modified adjusted gross income exceeds $106,000 for single filers or $212,000 for married couples filing jointly. These surcharges are based on income reported two years earlier, so your 2025 income will determine your 2027 Part B premium.