MAGI Calculator for Medicare

How to Use This Calculator — Step by Step

1. Find your AGI on your tax return. Look at your most recent federal income tax return (IRS Form 1040). Your Adjusted Gross Income is on Line 11. This is your starting point.
2. Find your tax-exempt interest. Look at Form 1040 Line 2a — this is tax-exempt interest income, most commonly from municipal bonds or tax-exempt bond funds. Add this to your AGI.
3. Add foreign earned income exclusions (if applicable). If you excluded any income under the Foreign Earned Income Exclusion (Form 2555) or had tax-exempt U.S. territory income, include that amount.
4. Enter the amounts and read your Medicare MAGI. Enter each value in the calculator. Your Medicare MAGI is the sum — compare it to the IRMAA thresholds shown to determine your bracket.

What Income Is Included in Medicare MAGI — and Why It Matters

Many retirees assume that their Adjusted Gross Income (AGI) on their tax return is the number Medicare uses to check for premium surcharges. However, Medicare uses a special definition called Medicare MAGI, which adds specific tax-exempt income sources back into your AGI.

What Income Is Included in IRMAA Calculation?

Your Medicare MAGI includes all standard components of your AGI plus specific required add-backs:

• Adjusted Gross Income (IRS Form 1040 Line 11): Includes pension income, traditional IRA/401(k) withdrawals, taxable Social Security benefits, wages, interest, dividends, and capital gains.
• Tax-Exempt Interest (IRS Form 1040 Line 2a): Interest from municipal bonds and tax-exempt mutual funds. Social Security legally requires this to be added back.
• Foreign Earned Income Exclusion (Form 2555): Any income excluded under foreign earned income or foreign housing rules.
• Tax-Exempt U.S. Territory Income: Income from Puerto Rico, Guam, American Samoa, or Northern Mariana Islands not included in AGI.

What Income Is Excluded from Medicare MAGI?

Certain retirement income sources do not count toward Medicare MAGI, making them valuable tools for managing IRMAA brackets:

• Roth IRA Distributions: Qualified withdrawals from Roth IRAs and Roth 401(k)s are completely tax-free and excluded from Medicare MAGI.
• Health Savings Account (HSA) Withdrawals: Qualified distributions used for medical expenses.
• Non-Taxable Social Security: The portion of Social Security benefits exempt from federal tax.
• Life Insurance Payouts & Inheritances: Tax-free policy proceeds and non-taxable gifts.

Common Mistakes and How to Avoid Them

Using Your Current Year's Income Instead of the Two-Year-Old Return

SSA receives IRS data from 2 years prior. If you base your MAGI on this year's income when the relevant return was two years ago, you may plan for the wrong IRMAA bracket.

The fix is to always identify which tax year SSA is using for your current coverage year, then pull that specific return.

Forgetting Line 2a — Tax-Exempt Municipal Bond Interest

Tax-exempt interest is the most commonly missed add-back. Many retirees holding muni bonds are surprised when IRMAA applies because they only looked at their AGI.

The fix is to ensure that even if your muni interest is small, you add it. A $5,000 municipal bond payment could push you over an IRMAA cliff threshold.

Assuming Roth IRA Withdrawals Are Always Invisible to IRMAA

Qualified Roth IRA distributions are excluded from Medicare MAGI, but non-qualified distributions are not. If you take early or non-qualified distributions from a Roth, those may count.

The fix is to confirm that your Roth IRA is at least 5 years old and you are 59½ or older before treating distributions as MAGI-free.

Frequently Asked Questions: MAGI for Medicare