IRMAA in 2027: How Your Income Sets Your Medicare Premiums — and the 2025 Tax Return That Decides It

If you’re on Medicare, your premium isn’t the same for everyone. Higher-income retirees pay a surcharge called IRMAA — the Income-Related Monthly Adjustment Amount — on top of the standard Part B and Part D premiums. And the part most people miss: your 2027 premium is decided by the tax return you already filed, for 2025.

Here’s how it works for 2027, what the brackets are, and what you can still control.

Note: CMS hasn’t officially announced the 2027 Part B premium yet. The premium amounts below are projected from the Medicare Trustees’ $209.50 estimate. The income thresholds are calculated from the statutory CPI-U formula, which has reproduced CMS’s official thresholds exactly for 2024, 2025, and 2026.

1. What IRMAA is

IRMAA is a surcharge added to your Medicare Part B premium — and a separate one added to Part D — when your modified adjusted gross income (MAGI) is above a set threshold. It applies per person, so a married couple on Medicare pays the surcharge twice.

The standard Part B premium for 2027 is projected at $209.50 a month, up from $202.90 in 2026. IRMAA tiers are fixed multiples of that standard premium, so the top tier pays 340% of it.

2. The two-year lookback — your 2025 return sets your 2027 premium

Medicare doesn’t look at this year’s income. It looks back two years:

• 2027 premiums come from your 2025 tax return (already filed — closed, appeal only)
• 2028 premiums come from your 2026 tax return (this is the year you can still plan)

That means a big income year in 2025 — a Roth conversion, a large capital gain, selling a property — shows up in your 2027 Medicare bill, even if your income has since dropped.

3. The 2027 IRMAA brackets (projected)

Based on your 2025 MAGI.

Tier	Single / head of household	Married filing jointly	Part B / month	Part D add-on / month
Standard	$112,000 or less	$224,000 or less	$209.50	$0
Tier 1	$112,001 – $141,000	$224,001 – $282,000	$293.30	+$15.40
Tier 2	$141,001 – $176,000	$282,001 – $352,000	$419.00	+$39.70
Tier 3	$176,001 – $211,000	$352,001 – $422,000	$544.70	+$64.00
Tier 4	$211,001 – $499,999	$422,001 – $749,999	$670.40	+$88.30
Tier 5	$500,000 or more	$750,000 or more	$712.30	+$96.40

For comparison, the 2026 first threshold was $109,000 single / $218,000 joint, with a $202.90 standard premium.

A few details:

• The middle tier boundaries could be $1,000 higher than shown (for example, Tier 1 up to $142,000 instead of $141,000). The Bureau of Labor Statistics published no CPI-U for October 2025, and how CMS treats that month moves the middle boundaries by $1,000. The first tier ($112,000 / $224,000) and the top tier ($500,000 / $750,000) are the same either way.
• The top tier is frozen by law — $500,000 single / $750,000 joint — and isn’t indexed until after 2027.
• Married filing separately is much harsher: if you lived with your spouse during 2025, MAGI above $112,000 lands you straight in Tier 4, and $388,000 or more puts you in Tier 5. If you lived apart all year, the single column applies.
• Part B premiums by tier move if CMS announces a different standard premium than $209.50. Part D add-ons are calculated from the $41.33 base beneficiary premium CMS already announced for 2027.

4. Part D in 2027

• Part D deductible cap: $700, up from $615 in 2026 (many plans charge less)
• Part D out-of-pocket cap: $2,400, up from $2,100 — once you hit it, you pay nothing more for covered drugs that year
• Part D base beneficiary premium: $41.33, up from $38.99
• The Part D IRMAA add-on is paid on top of your drug plan’s own premium

Medicare open enrollment ends December 7.

5. The cliff — $1 over costs the full tier

IRMAA is a cliff, not a slope. Crossing a tier boundary by a single dollar applies the entire surcharge for the full year, on both Part B and Part D.

One dollar over $112,000 in 2025 MAGI as a single filer means about $84 more per month on Part B plus $15.40 on Part D — roughly $1,190 extra for the year — for that one dollar of income.

6. What counts in MAGI

Your IRMAA MAGI is your adjusted gross income (Form 1040, line 11) plus:

• Tax-exempt interest (line 2a) — yes, muni bond interest counts
• Excluded foreign earned income or housing
• Education savings-bond interest
• Certain Puerto Rico / American Samoa income

Nontaxable Social Security is not added. But a Roth conversion is ordinary income, so it lands in MAGI — a conversion done in 2026 can push you into a higher IRMAA tier for 2028.

7. What you can still control

2027 is set — unless you appeal. You can’t change 2025 income now. But if you had a qualifying life-changing event — retirement, work reduction, marriage, divorce, or the death of a spouse — you can ask SSA to reconsider using your current income with Form SSA-44.

2026 income is the one to plan. Your 2026 MAGI sets your 2028 IRMAA. That’s the year where timing still matters:

• Time Roth conversions carefully — spread them across years to stay under a tier boundary
• Watch capital gains realizations and year-end distributions near a threshold
• Remember the cliff: $1 over a boundary costs the whole tier

What should you do now?

1. Find your 2025 MAGI (Form 1040 line 11 plus tax-exempt interest) and check which 2027 tier it puts you in.
2. If you had a life-changing event in 2025 or 2026, consider a Form SSA-44 appeal.
3. Plan your 2026 income with 2028 IRMAA in mind — especially Roth conversions and large gains.
4. Watch for the official CMS announcement of the 2027 Part B premium and deductible, expected by mid-November — the final premium could land above or below the $209.50 projection.

Bottom line: IRMAA is one of the easiest Medicare costs to overlook and one of the most expensive to trip over by accident. The two-year lookback means today’s income decisions are tomorrow’s premiums — plan them together.

This post is for general information only and isn’t tax or financial advice. Talk to a professional about your specific situation.

Sources: 2026 Annual Report of the Medicare Boards of Trustees; 42 U.S.C. §1395r(i); CMS CY2027 Rate Announcement. 2027 Part B premium and tier amounts are projected pending the official CMS announcement.