Social Security COLA vs Medicare Part B: 5-Year Erosion Across Income Brackets — Premiums

Social Security COLA vs Medicare Part B premiums is the annual calculation that determines how much of a retiree's cost-of-living raise actually stays in their pocket after healthcare costs are deducted. Social Security COLA is the annual adjustment to benefits based on CPI-W inflation, while Medicare Part B is the outpatient coverage premium that grows independently of Social Security formula. Every year, retirees watch the COLA announcement with anticipation, hoping for a meaningful increase in their monthly benefit. But the real question isn't how much the COLA adds — it's how much of that increase you actually get to keep after Medicare Part B premiums rise. Rising Part B premiums consistently consume a significant portion of that raise, leaving many retirees with a net benefit that barely keeps pace with inflation.

2026 Cost Breakdown: COLA Receipt vs Part B Bite

Every year, retirees watch the Social Security COLA announcement with anticipation, hoping for a meaningful increase in their monthly benefit. But the real question isn't how much the COLA adds — it's how much of that increase you actually get to keep after Medicare Part B premiums rise. This is the core tension in "social security cola vs medicare part b premiums": the annual cost-of-living adjustment is designed to protect purchasing power, yet rising Part B premiums consistently consume a significant portion of that raise, leaving many retirees with a net benefit that barely keeps pace with inflation.

The 2026 Social Security COLA is 2.8%, adding approximately $56 per month to the average $1,976 monthly benefit.¹ Meanwhile, the Medicare Part B standard premium rises to $202.90 per month in 2026, up from $185 in 2025 — a $17.90 increase.²

Here is how that $56 COLA breaks down for a retiree at the average benefit level:

For the average retiree, nearly one-third of the 2026 COLA is immediately absorbed by the Part B premium increase alone. This does not account for Part D premium changes, Medigap increases, or IRMAA surcharges that apply to higher-income beneficiaries.

The COLA vs. Medicare Part B Premium: A 5-Year History

The gap between Social Security COLA increases and Medicare Part B premium growth has widened significantly over the past five years. From 2022 through 2026, cumulative Social Security COLAs totaled approximately 19.5%¹, while Medicare Part B premiums rose by roughly 28% over the same period².

The 2023 anomaly — a rare premium decrease — was driven by the lower-than-expected cost of the Alzheimer's drug Aduhelm, which temporarily reduced Part B spending projections. That one-year reprieve aside, the trend is clear: Part B premiums are rising faster and more consistently than COLAs.

How Rising Part B Premiums Have Eaten Into Your COLA

The cumulative effect of Part B premium increases on retiree purchasing power is stark. From 2010 to 2026, Medicare Part B premiums grew 121%, from $96.40 to $202.90 per month.³ Over that same 16-year period, cumulative Social Security COLAs totaled approximately 45%.³

Consider a retiree who began receiving Social Security in 2010 with a $1,200 monthly benefit and the standard Part B premium of $96.40. By 2026, that same retiree's benefit would have grown to roughly $1,740 through COLAs, but their Part B premium would have risen to $202.90.³ The net result: the Part B premium consumed 8% of their gross benefit in 2010, but consumes 11.7% in 2026 — a 46% increase in the premium-to-benefit ratio.³

For a retiree with the average 2026 benefit of $1,976, the standard Part B premium of $202.90 consumes 10.3% of gross benefits before any IRMAA surcharge is applied.⁴ This means the purchasing power of each COLA dollar is effectively diluted by the compounding growth of healthcare costs embedded in the Medicare system.

Income Bracket Breakdown: Low, Middle, and High Earners Compared

The impact of Part B premium increases varies dramatically by income bracket. The table below shows how three hypothetical retirees fare under the 2026 numbers:

The low-income retiree feels the Part B premium most acutely as a percentage of their benefit, even without IRMAA. The high-income retiree faces a total Medicare cost of nearly $600 per month¹, consuming over one-fifth of their Social Security benefit.

The IRMAA Trap: When Higher Income Triggers Steeper Premiums

The Income-Related Monthly Adjustment Amount (IRMAA) adds $74.00 to $395.60 per month on top of the standard Part B premium for beneficiaries whose modified adjusted gross income (MAGI) exceeds certain thresholds.² In 2026, the first IRMAA tier begins at $206,000 for single filers and $412,000 for joint filers.

The trap is the two-year lookback rule. Your 2026 Part B premium is based on your 2024 tax return. Suppose you sold a business, exercised stock options, or took a large retirement account distribution in 2024. That one-time income spike can push you into an IRMAA tier for 2026, even though your ongoing retirement income is much lower.

For example, a retiree who took a $150,000 Roth conversion in 2024 might see their MAGI jump to $230,000 for that year. Under the 2026 IRMAA brackets, that single filer would pay an additional $74.00 per month — $888 per year — for two full years before the surcharge can be reassessed¹.

Why Your Net Social Security Benefit May Be Shrinking

The net Social Security benefit — what actually lands in your bank account after Medicare premiums are deducted — has been growing more slowly than the gross benefit for years. This is the direct result of Part B premium growth outpacing COLA increases.

The hold-harmless provision protects most existing beneficiaries from a net decrease in their Social Security payment when Part B premiums rise. Under this rule, a beneficiary's Social Security check cannot decrease from one year to the next due to a Part B premium increase alone.⁵ However, this protection does not apply to new enrollees, high-income beneficiaries subject to IRMAA, or those who have their Part B premiums paid by state Medicaid programs.

For new enrollees in 2026, the full $202.90 premium is deducted from day one, with no hold-harmless cushion. This means a retiree who starts benefits in 2026 faces the full brunt of the premium increase immediately, while existing beneficiaries may see their net benefit stagnate as the hold-harmless provision defers premium increases into future years.

Strategic Withdrawals: Managing 401k Income to Control IRMAA

Managing your modified adjusted gross income (MAGI) is the most effective tool for controlling IRMAA surcharges. Since IRMAA is based on your tax return from two years prior, you have a two-year window to plan your income strategically.

One approach is to use a Roth conversion ladder in lower-income years before Required Minimum Distributions (RMDs) begin. By converting smaller amounts each year, you can stay below the IRMAA threshold while gradually moving assets into tax-free accounts.

Another strategy is to use qualified charitable distributions (QCDs) from your IRA once you turn 70½. QCDs count toward your RMD but do not increase your MAGI, making them a powerful tool for managing IRMAA exposure. A retiree with a $30,000 RMD who directs $10,000 to a QCD reduces their MAGI by that same amount, potentially staying below an IRMAA threshold.

What the Next 5 Years Look Like for COLA and Part B Costs

Projecting future COLA and Part B premium trends requires looking at the underlying drivers. Social Security COLAs are tied to the Consumer Price Index for Urban Wage Earners and Clerical Workers (CPI-W), while Part B premiums are set based on projected program costs, including physician payments, hospital outpatient services, and the growing use of expensive specialty drugs.

The Medicare Trustees Report projects that Part B premiums will continue to grow at roughly 5% annually over the next decade, driven by rising healthcare costs and an aging population. If COLAs average 2.5-3% over the same period — consistent with recent inflation trends — the gap will continue to widen.

For a retiree with the average benefit, this means the Part B premium could consume roughly 12-13% of gross Social Security benefits by 2030¹, up from an estimated 10.3% in 2026². For high-income retirees subject to IRMAA, the percentage could approach a quarter or more, depending on how the IRMAA brackets are adjusted for inflation.

Your Next Step

At Smart Money After 60, we recommend reviewing your 2024 tax return to determine your MAGI and compare it against the 2026 IRMAA thresholds. For a personalized projection of your net Social Security benefit after Medicare costs, use the Medicare Premium Calculator at Medicare.gov.