Chapter 11: The Two-Year Lookback
The worksheets from Chapter 11 of Fifty-Five. Type your own numbers, or try an example from the book to see how each one works.
The 2026 IRMAA table
Your MAGI from two years earlier picks your row. Type your MAGI into a calculator below and it finds the row for you. Or find it here and work the paper worksheet.
| Row | Individual return MAGI | Joint return MAGI | Part B premium, a month | Part D surcharge, a month |
|---|---|---|---|---|
| 1 | $109,000 or less | $218,000 or less | $202.90 | $0.00 |
| 2 | Over $109,000 up to $137,000 | Over $218,000 up to $274,000 | $284.10 | $14.50 |
| 3 | Over $137,000 up to $171,000 | Over $274,000 up to $342,000 | $405.80 | $37.50 |
| 4 | Over $171,000 up to $205,000 | Over $342,000 up to $410,000 | $527.50 | $60.40 |
| 5 | Over $205,000 and under $500,000 | Over $410,000 and under $750,000 | $649.20 | $83.30 |
| 6 | $500,000 or more | $750,000 or more | $689.90 | $91.00 |
Married filing separately, if you lived with your spouse at any time in the year
| Row | MAGI | Part B premium, a month | Part D surcharge, a month |
|---|---|---|---|
| 1 | $109,000 or less | $202.90 | $0.00 |
| 2 | Over $109,000 and under $391,000 | $649.20 | $83.30 |
| 3 | $391,000 or more | $689.90 | $91.00 |
MAGI here is your adjusted gross income plus any tax-exempt interest. The Part D surcharge is added to your plan's own premium. Each person on Medicare pays these amounts.
Where these figures come from: The 2026 Part B premium and Part D surcharge for every row of the IRMAA table, used when you type your MAGI (CMS, 2026 Medicare Parts A & B Premiums and Deductibles); The 2026 IRMAA income lines for individual, joint and married-filing-separately returns (SSA, Premiums: Rules for Higher-Income Beneficiaries). They are the 2026 amounts and they change every year.
Which year's income sets your premium
Which tax return Social Security will look at for a premium year, or which future premium a decision you make today will affect.
The formula: Looking back: Premium year − 2 = The tax year that sets it. Looking ahead: The year you earn the income + 2 = The premium year it affects. Ages work the same way: subtract 2 to look back, add 2 to look ahead.
The calculator needs JavaScript. The paper worksheet below does not: it is the same arithmetic, written out.
The paper worksheet
Looking back: Premium year ______ − 2 = Tax year that sets it ______
Looking ahead: Year you earn the income ______ + 2 = Premium year it affects ______
Walk through it, step by step
- Decide which way you're looking. Back: "Which return sets this year's premium?" Ahead: "Which premium will this income change?"
- Looking back: write the premium year on the first blank. Subtract 2. Write the answer. That is the tax year.
- Looking ahead: write the year you will earn the income. Add 2. Write the answer. That is the premium year.
- To find your MAGI for a past tax year, open that year's Form 1040. Take your adjusted gross income and add the tax-exempt interest shown on the same form.
- Compare that MAGI with the IRMAA table for the premium year, in the next section.
Check your answer
- The two years should always be exactly 2 apart.
- Looking back, your answer must be an earlier year. Looking ahead, it must be a later year. If not, you added when you should have subtracted, or the other way around.
Figures this worksheet uses, and where they come from: The two-year lookback: a premium year is generally set by the tax return from two years before (SSA, Premiums: Rules for Higher-Income Beneficiaries).
What IRMAA costs you for a year
One yearly dollar amount for your household: what your row of the IRMAA table adds on top of the standard premium.
The formula: (Your Part B premium − $202.90) + Your Part D surcharge = Extra per month, per person. Then × 12 = Extra per year, per person. Then × the number of people on Medicare = Extra per year for the household.
The calculator needs JavaScript. The paper worksheet below does not: it is the same arithmetic, written out.
The paper worksheet
(Your Part B premium $__________ − $202.90) + Your Part D surcharge $__________ = Extra per month $__________
Extra per month $__________ × 12 = Extra per year, per person $__________
Extra per year, per person $__________ × People on Medicare ______ = Household extra per year $__________
Walk through it, step by step
- Find your MAGI for the tax year that sets this premium (use the worksheet above to find the year).
- Pick your column: individual return or joint return.
- Go down that column to the row your MAGI fits. "Over $109,000 up to $137,000" means more than $109,000 and no more than $137,000.
- If your MAGI is in the first row, stop. Your extra cost is $0.
- Write the Part B premium from your row on the first blank. Subtract $202.90.
- Write the Part D surcharge from your row. Add it to the answer from Step 5. That is your extra per month.
- Multiply by 12. On paper, multiply by 10, multiply by 2, and add the two answers.
- Multiply by the number of people in your household on Medicare: 1 or 2.
- Write the answer on the last blank.
Check your answer
- For 2026, no one pays more than $6,936 extra per person for the year. That is the top row: ($689.90 − $202.90 + $91.00) × 12 = $6,936. If your answer per person is bigger, recheck your row.
- Your per-person yearly answer should match the steps chart in Chapter 12 for your row.
Figures this worksheet uses, and where they come from: The 2026 standard Part B premium, $202.90 a month (CMS, 2026 Medicare Parts A & B Premiums and Deductibles); The 2026 top-row IRMAA amounts used for the $6,936 check: Part B $689.90 and Part D surcharge $91.00 a month (CMS, 2026 Medicare Parts A & B Premiums and Deductibles); The 2026 Part B premium and Part D surcharge for every row of the IRMAA table, used when you type your MAGI (CMS, 2026 Medicare Parts A & B Premiums and Deductibles); The 2026 IRMAA income lines for individual, joint and married-filing-separately returns (SSA, Premiums: Rules for Higher-Income Beneficiaries).