IRMAA Basics
Understanding the IRMAA Two-Year Look-Back Rule for Medicare Premiums
Verified against SSA POMS as of July 28, 2026
The short answer
IRMAA two-year look-back rule refers to the Social Security Administration's method of using federal income tax return data from two years prior (PY-2) to calculate the Income-Related Monthly Adjustment Amount (IRMAA) for Medicare premiums. If data from two years prior is unavailable, the IRS provides data from three years prior (PY-3). Beneficiaries can request a new determination if their PY-2 MAGI becomes available. Source: HI 01120.055
The Two-Year Look-Back Rule
The Social Security Administration (SSA) uses the adjusted gross income (AGI) and tax-exempt interest of a Medicare beneficiary to determine if an income-related monthly adjustment amount (IRMAA) applies, typically using data from two years prior to the premium year (PY-2). If this data is unavailable, SSA uses data from three years prior (PY-3). Beneficiaries are informed about the IRMAA and their appeal rights via notices. Reference: HI 01101.035
As an example, if you are applying for Medicare for all or any part of 2026, the Social Security Administration will request your 2024 Form 1040 Tax information from the IRS. If your 2024 form 1040 is unavailable, the IRS will provide 2023 Form 1040 information to the SSA.
HI 01101.035 View source ›Requesting a New Determination
Beneficiaries who have two-year old data that SSA hasn't used, but relied on three-year old data instead, can request a new determination. The request can be made any time during the affected year, with one exception: if a beneficiary receives a notice in the last three months of the year, they have until March 31 of the following year to request a correction. SSA will apply the revised determination only to the current premium year. Reference: HI 01120.055
HI 01120.055 View source ›Providing Evidence
SSA requires a signed copy of the beneficiary's filed federal income tax return for the tax year two years prior to the premium year to support a new IRMAA determination. For electronic filings, beneficiaries must print and sign their electronic returns. Reference: HI 01120.055
HI 01120.055 View source ›Handling of Incorrect IRS Data
If a beneficiary can prove that the IRS provided incorrect data leading to their IRMAA, they may request a new determination. They must provide an IRS document acknowledging the error. SSA uses the adjusted gross income (AGI) and tax-exempt interest to verify the new information. Reference: HI 01120.050
HI 01120.050 View source ›Frequently asked
What happens if my IRMAA was based on 3-year old data?
If the SSA used 3-year old data and you have 2-year old data available, you can request a new IRMAA determination based on the newer data. See section HI 01120.055.
How does SSA determine the tax year for my Medicare premium?
IRMAA is typically determined using tax data from two years prior to the premium year, provided by the IRS. If that data is unavailable, data from three years prior is used. Refer to section HI 01101.035.
How do I provide new tax information to SSA for IRMAA?
Provide a signed copy of your filed federal return from two years prior to the premium year. If filed electronically, ensure it is printed and signed as required in HI 01120.055.
Can I correct my IRMAA if the IRS made an error?
Yes, you can request a new determination using corrected IRS data if you have proof of the error. Details are in section HI 01120.050.
What kind of tax proof is needed for a new IRMAA determination?
Submit a signed copy of your federal tax return for the year two years prior to the premium year. Refer to HI 01120.055 for more information.