IRMAA Calculator: How to Use It

What this calculator does

The IRMAA Calculator takes your MAGI and filing status and shows which IRMAA tier you fall into, your total Part B and Part D monthly surcharges, and your annual Medicare premium cost versus the standard amount. It also shows what income level would push you into the next tier, which is useful for planning Roth conversions, RMDs, and other income events.

Because IRMAA is based on income from two years prior, the calculator lets you enter your expected MAGI for the current year and see the premium impact in two years. If you're 63, enter your 2026 projected income to see what you'll pay for Medicare starting in 2028.

What each input means

Modified Adjusted Gross Income

Your MAGI for IRMAA purposes is your AGI from your tax return plus any tax-exempt interest (typically from municipal bonds). Find your AGI on line 11 of Form 1040. Add back any tax-exempt interest from line 2a of Schedule B. That total is your IRMAA MAGI.

Common income sources that count: wages, self-employment, taxable Social Security (up to 85% of benefits), traditional IRA and 401(k) distributions, pensions, annuities, capital gains, dividends, rental income, and municipal bond interest. Roth IRA qualified distributions don't count. HSA distributions for qualified medical expenses don't count.

Filing status

Single filers and married filing jointly have different threshold tables. Married filing separately is a separate (much harsher) table. If you're married and filing separately, the first IRMAA tier starts at around $106,000 MAGI, the same dollar amount that puts single filers into the first tier but married joint filers into the second. Don't file separately unless there's a compelling tax reason.

The 2026 IRMAA tiers

For single filers in 2026, the surcharge tiers are approximately:

• Under $106,000: standard premium ($185/month Part B, standard Part D)
• $106,000 to $133,000: Part B surcharge of $74.00/month
• $133,000 to $167,000: Part B surcharge of $185.00/month
• $167,000 to $200,000: Part B surcharge of $295.90/month
• $200,000 to $500,000: Part B surcharge of $406.90/month
• Above $500,000: Part B surcharge of $443.90/month

Married filing jointly thresholds are double the single amounts. Part D surcharges are additional and vary by plan. The calculator applies both. These amounts are indexed for inflation and change each year.

The two-year lookback

SSA uses your tax return from two years ago to set your current Medicare premiums. 2026 Medicare premiums come from your 2024 tax return. If your 2024 income was high because you did a large Roth conversion, sold a business, or had a one-time capital gain, you'll pay elevated Medicare premiums in 2026 even if your 2026 income is much lower.

This is why people planning large income events in their early 60s need to think about Medicare timing. Doing a large Roth conversion at 63 can raise your Medicare premiums at 65 and 66 before the effect wears off.

Appealing IRMAA: Form SSA-44

If your income dropped significantly due to a qualifying life event (retirement, divorce, death of spouse, loss of pension), you can appeal using SSA Form SSA-44. SSA will use a more recent year's income or a current income estimate. You'll need documentation of the event and proof of the income change. Submit the form to your local Social Security office. The appeal can be filed at any time during the year and takes effect the following month if approved.