How the IRMAA income lookback sets your first Medicare premium
IRMAA’s income lookback runs two years behind, so the return you file next spring prices the first Medicare premium you will pay. Here is the timeline.
In This Article
The Medicare bill you are setting right now
Medicare does not price your Part B premium on what you earn today. The IRMAA income lookback means the Social Security Administration reads a tax return that is already two years old. The surcharge rides on two of Medicare’s five separate bills, not on an invoice of its own.
If you are 63 or 64
The tax year you are living through sets your first Medicare premium. It closes December 31.
If you are already enrolled
Your premium is locked to a return filed two years ago. If your income has since fallen, Section 7 is your section.
ℹ️ Financial Disclaimer: This article is educational, not personalized investment, tax, lending, credit, insurance, or debt-relief advice. Your IRMAA outcome depends on your own return, filing status, and enrollment date. Confirm your position with a fiduciary advisor, a CPA, or a qualified tax attorney before acting.
How the two-year lookback actually works
The IRMAA income lookback is the two-year gap between the tax year Social Security measures and the year you pay. Your 2024 return sets 2026, your 2025 return sets 2027, and your 2026 return sets 2028.
Which tax return Social Security pulls
Social Security uses the most recent return the Internal Revenue Service has made available, which in practice is the one filed two years earlier. Nothing filed later reopens a priced year.
What counts as your MAGI
🔍 How It Works: Social Security’s program manual defines modified adjusted gross income for IRMAA as adjusted gross income plus tax-exempt interest — line 11 of your Form 1040, with municipal bond income added back.
What each 2026 IRMAA bracket costs per year
The standard 2026 Part B premium is $202.90 a month. Above the threshold a surcharge applies to Part B and Part D together, per person rather than per household.
The 2026 brackets and what they add
| 2024 MAGI (single) | 2024 MAGI (joint) | Part B total | Part D surcharge | Key detail: added cost per person, per year |
|---|---|---|---|---|
| $109,000 or less | $218,000 or less | $202.90 | $0.00 | No surcharge |
| $109,001–$137,000 | $218,001–$274,000 | $284.10 | $14.50 | $1,148.40 |
| $137,001–$171,000 | $274,001–$342,000 | $405.80 | $37.50 | $2,884.80 |
| $171,001–$205,000 | $342,001–$410,000 | $527.50 | $60.40 | $4,620.00 |
| Over $205,000, under $500,000 | Over $410,000, under $750,000 | $649.20 | $83.30 | $6,355.20 |
| $500,000 or more | $750,000 or more | $689.90 | $91.00 | $6,936.00 |
Monthly figures: CMS, 2026 Medicare Parts A & B Premiums and Deductibles, November 14, 2025. Annual column calculated by FinanceAuthorityHub as (Part B surcharge + Part D surcharge) × 12. Tier-by-tier detail: IRMAA brackets and income tiers.
📊 Data Point: Income-related amounts affect roughly 8% of people with Medicare Part B — Source: Centers for Medicare & Medicaid Services, November 2025.
Why one dollar can cost $1,148
⚠️ Costly Mistake: IRMAA is a cliff, not a phase-in. A single filer at $109,000 of 2024 MAGI pays nothing extra; at $109,001 the full first tier applies for twelve months — $974.40 on Part B plus $174.00 on Part D.
The married-filing-separately trap
Separate filers who lived with a spouse skip the middle tiers: above $109,000 and below $391,000, the standard Part B premium becomes $649.20 plus an $83.30 Part D surcharge. It is one reason what a married couple pays for Medicare can hinge on filing status alone.
Why age 63 is the year that matters
Subtract two from the year you turn 65. That is the tax year that sets your first Medicare premium.
Your 63-to-65 timeline
| Age you turn in 2026 | Year you turn 65 | First premium year | Tax year that sets it | Key detail |
|---|---|---|---|---|
| 63 | 2028 | 2028 | 2026 | Open — closes December 31 |
| 64 | 2027 | 2027 | 2025 | Closed — already filed |
| 65 | 2026 | 2026 | 2024 | Closed — premium already set |
Calculated by FinanceAuthorityHub from the two-year lookback and Medicare’s age-65 eligibility.
What this means if you turn 63 this year
The return you file next spring is what Social Security reads in late 2027 to price your 2028 premium. It is the last return you can still influence before Medicare starts.
If you plan to delay Part B
Employer coverage past 65 pushes your first premium year forward, and the lookback year moves with it. Subtract two from the year your Part B coverage actually begins.
Income events at 63 that show up at 65
These are ordinary transactions, not mistakes. Each is invisible to Medicare for two years.
Retirement account moves
A Roth conversion is ordinary income in the year you convert, so converting at 63 lands in the return that prices your first premium. Timing is covered in our Roth conversion deadline guide.
Selling a home or a business
Only gain above the exclusion counts. IRS Topic no. 701 allows up to $250,000 of main-home gain to be excluded, or $500,000 jointly, when the ownership and use tests are met.
Severance, stock, and final-year pay
A final bonus, exercised options, or an accrued-leave payout all land in the same MAGI. Model the year in our capital gains tax calculator.
✅ Action Step: Ask a CPA: if I close this transaction in 2026 instead of 2027, which side of the IRMAA threshold does each year put me on?
What you can still change before the year closes
Part of this is already decided. Naming which part stops you worrying about the wrong year.
What is already fixed
Turn 64 or 65 this year and the return that prices your first premium is filed. Planning moves to the year after.
What is still open
Turn 63 and every remaining decision lands in that return — distributions, realized gains, deductible contributions, and whether you delay Social Security. Project the year in our income tax calculator.
What the 2027 and 2028 brackets will look like
💡 Expert Note: CMS publishes each year’s premiums and IRMAA amounts in late autumn; the 2026 figures were released November 14, 2025. Anyone showing you 2027 brackets today is estimating, not quoting.
If your income already dropped, file Form SSA-44
Form SSA-44 is how you ask Social Security to price your premium on a more recent year. File it after your determination notice arrives, not before.
What counts as a life-changing event
Social Security lists marriage, divorce, the death of a spouse, loss of income, and an employer settlement payment. Our Form SSA-44 walkthrough and IRMAA after a spouse dies go further.
When to file
Send the form with proof of the drop. Social Security’s page on lowering an income-related adjustment amount sets out the upload, fax, mail, and appointment routes.
IRMAA lookback questions, answered
1. What is the IRMAA income lookback?
The two-year gap between the tax year Social Security measures and the year your Medicare premium applies.
2. Which tax year determines my 2026 Medicare premium?
Your 2024 return. Social Security uses the most recent return the IRS has made available.
3. Why does age 63 matter for Medicare premiums?
Turn 63 in 2026 and your 2026 return sets the premium for 2028, your first Medicare year.
4. What income counts toward IRMAA?
Adjusted gross income from line 11 of Form 1040, plus tax-exempt interest such as municipal bond income. Confirm your MAGI with a CPA.
5. How much does the first IRMAA bracket cost per year?
The first tier adds $1,148.40 per person: $974.40 on Part B and $174.00 on Part D.
6. Is IRMAA a cliff or a phase-in?
A cliff. Crossing a threshold by one dollar triggers the full tier surcharge for twelve months.
7.Does IRMAA apply per person or per couple?
Per person. A married couple with both spouses enrolled in Medicare pays the surcharge twice.
8. Can I lower IRMAA after a life-changing event?
Yes. Form SSA-44 asks Social Security to use a more recent year after a qualifying event.
9. Do Roth conversions increase IRMAA?
Yes. A conversion is ordinary income in the year you convert, raising that year’s MAGI. Ask a CPA before converting near a threshold.
10. Does selling my house trigger IRMAA?
Only gain above the $250,000 single or $500,000 joint exclusion counts toward MAGI. A CPA should confirm your excluded gain.
11. Are the 2027 IRMAA brackets published yet?
No. CMS publishes each year’s figures in late autumn, so 2027 amounts are not official.
What to do before December 31
Pull last year’s Form 1040. Add line 11 to your tax-exempt interest, compare that total against the bracket table above, and measure the gap to the next threshold. What Medicare costs across a full year shows what the premium sits beside.
✅ Action Step: Take that number and your projected year-end MAGI to a CPA and ask which IRMAA tier your first Medicare year lands in.
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Informational disclaimer
The content on Finance Authority Hub is provided for general informational and educational purposes only and should not be considered personalized financial, investment, tax, legal, or professional advice. Financial decisions depend on your individual goals, income, risk tolerance, location, and regulatory situation. Before acting on any information, strategy, estimate, or calculator result, consult a qualified licensed professional who can evaluate your specific circumstances.