Is IRMAA Calculated Every Year? Lookback and Adjustments

Yes, IRMAA is calculated every year. The Social Security Administration runs a fresh determination each fall for every Medicare beneficiary enrolled in Part B or Part D, pulling new income data from the IRS and reapplying the surcharge tiers to decide what you’ll pay the following year.¹ Because the data changes year to year, your surcharge can go up, go down, or disappear entirely without you doing anything.

How the Annual Determination Works

Federal law requires the SSA to reduce the government’s share of your Part B premium, and raise yours, whenever your income exceeds a set threshold.² To carry that out, the agency requests income data from the IRS for every Medicare beneficiary once a year. If your income falls above the lowest threshold, you owe a monthly surcharge on top of the standard Part B premium and, separately, on top of whatever your Part D plan charges.

The figure that drives everything is your modified adjusted gross income: your adjusted gross income from line 11 of Form 1040 plus any tax-exempt interest from line 2a.³ That one number places you into a tier, or clear of the tiers entirely. For 2026, the surcharge starts once MAGI exceeds $109,000 for an individual filer or $218,000 for a joint filer.⁴

Notices go out in November telling higher-income beneficiaries what their Part B and Part D adjustments will be for the coming year.⁵ If you owed a surcharge last year and don’t this year, or vice versa, that letter is usually where you’ll find out.

The Two-Year Lookback

Every annual determination uses tax data from two years before the coverage year.¹ Your 2026 IRMAA is based on the return you filed for tax year 2024. The agency works from two-year-old data because the IRS often hasn’t finished processing the immediately prior year’s returns when the Medicare year begins.

The practical effect is that your current premium reflects your past finances, not your present ones. A one-time income spike in the lookback year can drive a surcharge you’re still paying long after your income has returned to normal. The reverse is also true: if you had a big year but this year is quieter, the surcharge doesn’t catch up until the next determination.

When Your Surcharge Adjusts on Its Own

Because the SSA pulls fresh IRS data every fall, most changes work themselves out without a phone call. If your income was high two years ago and has since dropped, the next annual determination will reflect the lower income, and your surcharge will shrink or fall off entirely.¹ You don’t need to file anything to make that happen.

The one situation where the automatic cycle isn’t enough is an amended tax return. If you amend the return the SSA used to set your surcharge, contact the agency to update its records — call 1-800-772-1213 or send a signed copy of the amended return.⁶ If you don’t, the SSA may make retroactive corrections later, which can mean either extra charges or a refund.

Income Spikes That Just Have to Wait

Not every income increase can be appealed away. If the income in your lookback year was legitimately high — even for a one-time reason — you’ll usually owe the surcharge until the next annual recalculation moves on to a different tax year.⁷ Common examples that don’t qualify for relief:

Roth IRA conversions. The converted amount is added to MAGI for the year and can push you into a higher tier, but the conversion isn’t a life-changing event.
Capital gains from selling a home or investments. A one-time profit raises your lookback-year income without qualifying you for a reduction.
Required minimum distributions. Large withdrawals from retirement accounts count toward MAGI. Sending part of an RMD directly to a charity as a qualified charitable distribution can trim the taxable portion in future years.

In each case, the surcharge typically lasts one year, because the following year’s determination uses a different return. Timing large transactions with the two-year lookback in mind is often the only way to soften the impact.

When You Can Ask for a Mid-Year Recalculation

If your income dropped because of a qualifying life-changing event, you don’t have to wait for the next annual cycle. You can file Form SSA-44 and ask the SSA to use your current or expected income instead of the two-year-old tax data.⁶ The form asks you to identify the event, estimate your MAGI, and attach supporting documents.

Qualifying events are:⁷

Marriage
Divorce or annulment
Death of a spouse
Work stoppage or reduction (retirement, layoff, cutting hours)
Loss of income-producing property from a disaster or event beyond your control
Loss of pension income
Employer settlement payment

Each event has its own documentation. A work stoppage takes a statement from the employer with the date you stopped working, the employer’s name and location, and the type of separation.⁸ A spouse’s death takes a certified death certificate; a divorce takes a certified copy of the decree.⁶

You can submit the form online through your my Social Security account, by mail to your local Social Security office, or in person; you can also start the process by calling 1-800-772-1213.⁷ The SSA will use your estimate until it receives actual IRS data for that year, and will send a new determination letter with the adjusted premium and effective date. If your estimate turns out to be off, or you later amend the return, tell the SSA so the record stays current.

Filing SSA-44 is a request for a new initial determination, not a formal appeal. If the SSA denies it, or you disagree with the surcharge for a different reason, you have 60 days from receipt of the determination notice to file Form SSA-561 for reconsideration; the SSA treats the notice as received five days after its date.⁹ Additional levels of appeal are available after that, each with its own 60-day window.

What Happens If You Don’t Pay the Surcharge

The surcharge isn’t optional, and the annual recalculation doesn’t wipe out unpaid amounts. If you don’t pay the Part B surcharge, you enter a grace period that runs through the last day of the third month after the billing month; if the balance remains unpaid, Part B coverage terminates on the last day of that grace period.¹⁰ CMS may reinstate coverage without a gap if you show good cause and pay all overdue premiums within three months of termination.

Skipping the Part D surcharge can get you disenrolled from your prescription drug plan, even when that plan is part of Medicare Advantage or employer coverage. If you re-enroll later, you may still owe the unpaid surcharges, and your new Part D premium can be higher because of the coverage gap.

1
Social Security Administration. Medicare Annual Verification Notices – Frequently Asked Questions
2
Office of the Law Revision Counsel. 42 USC 1395r – Amount of Premiums for Individuals Enrolled Under This Part
3
Social Security Administration. POMS HI 01101.010 – Modified Adjusted Gross Income (MAGI)
4
Centers for Medicare & Medicaid Services. 2026 Medicare Parts A and B Premiums and Deductibles
5
Centers for Medicare & Medicaid Services. Guide to Consumer Mailings From CMS, Social Security, and Plans
6
Social Security Administration. Form SSA-44 – Medicare Income-Related Monthly Adjustment Amount – Life-Changing Event
7
Social Security Administration. Request to Lower an Income-Related Monthly Adjustment Amount (IRMAA)
8
Social Security Administration. POMS HI 01120.030 – Life Changing Event – Work Stoppage
9
Social Security Administration. POMS HI 01140.001 – Overview of the Appeals Process for the Income-Related Monthly Adjustment Amount
10
eCFR. 42 CFR Part 408 – Premiums for Supplementary Medical Insurance