IRMAA Basics
Understanding IRMAA and Modified Adjusted Gross Income for Medicare
Verified against SSA POMS as of July 29, 2026
The short answer
The Income-Related Monthly Adjustment Amount (IRMAA) is a surcharge applied to Medicare premiums based on your Modified Adjusted Gross Income (MAGI). MAGI is calculated as the sum of your adjusted gross income (AGI) from line 11a of 2025 IRS Form-1040 plus any tax-exempt interest income from line 2a of IRS Form-1040. Additionally, one-time incomes like capital gains from property sales or IRA withdrawals may be included in MAGI temporarily affecting your Medicare premium for a single year. CMS sets annual MAGI thresholds that determine the IRMAA tiers applied. Note that IRS Form1040 can and will change year to year.
What Counts as Income for IRMAA
IRMAA is determined using your Modified Adjusted Gross Income (MAGI), which combines the adjusted gross income from your tax return plus any tax-exempt interest income, and potentially includes one-time income events like capital gains or IRA withdrawals. These values are taken from your IRS Form 1040, with adjusted gross income located at line 11a and tax-exempt interest at line 2a.
HI 01194.105 View source ›How MAGI Affects IRMAA Premiums
The Income-Related Monthly Adjustment Amount (IRMAA) is a surcharge in addition to your Medicare premiums, based on MAGI. This surcharge is linked to CMS-set income thresholds. Premium adjustments are categorized by filing status, such as Single, Married Filing Jointly, or Married Filing Separately, and range from 35% to 85% of the total Medicare Part B cost based on income levels.
HI 01101.031 View source ›Calculating Modified Adjusted Gross Income (MAGI)
MAGI is calculated by adding your adjusted gross income (AGI) to tax-exempt interest income. Key lines from IRS Form-1040 are used, specifically line 11a for AGI, and line 2a for tax-exempt interest.
HBK 2501 View source ›Thresholds Impacting IRMAA Charges
MAGI thresholds that influence IRMAA are adjusted annually using the year-over-year Consumer Price Index for Urban Consumers (CPI-U) from the month ending in August. These thresholds determine the amount of IRMAA surcharge applied to your Medicare premiums.
HBK 2502Appealing an IRMAA Decision
Should you disagree with an IRMAA surcharge, SSA provides a structured appeals process. You can submit for reconsideration if you believe there is an error with your IRS-provided MAGI or if your income has reduced due to life-changing events.
HI 01140.001 View source ›Frequently asked
How is MAGI calculated for IRMAA?
MAGI is calculated by adding together the amounts from lines 2a and 11a of IRS Form 1040. This includes your adjusted gross income and any tax-exempt interest. Understanding these components is crucial for determining your IRMAA obligations.
What affects my IRMAA amount?
Your IRMAA amount is affected by your MAGI and tax filing status, according to thresholds set annually by CMS.
Can I appeal an IRMAA decision?
Yes, you can request an appeal if you believe there's an error by the IRS or if you have experienced a life-changing event that significantly changes your financial situation.
Does one-time income affect IRMAA?
Yes, one-time income such as capital gains can temporarily affect your IRMAA calculation for the year it occurred.
What can lower or eliminate my IRMAA surcharge?
Life-changing events such as marriage, divorce, death of a spouse, work stoppage or reduction, loss of income-producing property, loss of pension income, or an employer settlement payment can affect your MAGI and potentially alter your IRMAA charge. Using the wrong year tax return or incorrect tax return information provided to the SSA from the IRS may also be grounds for lowering the IRMAA surcharge.