IRMAA calculator: your 2026 Part B surcharge
TL;DR: Enter MAGI from two years before the premium year and your filing status. The calculator looks up your 2026 IRMAA tier using CMS's brackets, shows the Part B premium and surcharge per person, the annual cost for your household, and the income room before the next tier.
Educational only, not tax, legal, or investment advice. Examples are illustrations, not predictions. Rules and limits change; verify current figures and talk to a qualified professional about your situation.
Tells you exactly how far you are from the edge of the cliff. Medicare's Income-Related Monthly Adjustment Amount adds a surcharge to Part B (and Part D) premiums for higher-income beneficiaries. It's based on your tax return from two years earlier, and each tier is all-or-nothing. This calculator uses CMS's 2026 Part B figures so you can see your tier and, more usefully, your distance to the next one before you finalize a Roth conversion or a capital gain.
CPA Warning Label: IRMAA tiers are cliffs. The calculator tells you exactly where the edge is; it can't stop you from walking off it in December.
Inputs
- MAGI. For IRMAA, adjusted gross income plus tax-exempt interest. For 2026 premiums, that's your 2024 return. If you're planning this year's income, enter this year's projected MAGI to see roughly where you'd land two years from now (thresholds will be indexed, so treat results as approximate).
- Filing status. 1 for married filing jointly, 0 for single, head of household or qualifying surviving spouse. Married filing separately has a harsher schedule, described below, that this calculator doesn't model.
- People on Medicare. IRMAA is charged per person. A couple both on Part B pays it twice.
Tier lookup
| Tier | Single MAGI | Joint MAGI | Monthly Part B |
|---|---|---|---|
| 0 | $109,000 or less | $218,000 or less | $202.90 |
| 1 | up to $137,000 | up to $274,000 | $284.10 |
| 2 | up to $171,000 | up to $342,000 | $405.80 |
| 3 | up to $205,000 | up to $410,000 | $527.50 |
| 4 | under $500,000 | under $750,000 | $649.20 |
| 5 | $500,000 or more | $750,000 or more | $689.90 |
Source: CMS 2026 Medicare Parts A and B premiums fact sheet. Married filing separately (lived with spouse during the year): $109,000 or less pays $202.90, above that and under $391,000 pays $649.20, and $391,000 or more pays $689.90.
Annual surcharge
The surcharge is the tier premium minus the standard $202.90. The household annual figure multiplies that by 12 and by the number of people on Medicare. Part D IRMAA is added separately to your drug plan premium, and isn't included here; it's smaller but follows the same tiers.
Distance to next tier
"MAGI room before the next tier" is how much more income you could add without moving up. "How far above your tier's starting line" is how much you'd need to cut to drop down a tier. If you're $500 over a line, as in the first example below, finding $500 of deductions or deferring $500 of income is worth nearly $2,000 a year for a couple.
Examples
Illustration: married couple, both on Medicare, MAGI $218,500. Tier 1. Premium $284.10 each, surcharge $81.20 each per month, $1,948.80 a year for the household. They're $500 above the line and have $55,500 of room before tier 2.
Single filer, MAGI $100,000: tier 0, no surcharge, $9,000 of room.
Single filer, MAGI $180,000: tier 3, premium $527.50, surcharge $324.60 a month or $3,895.20 a year. They're $9,000 above the tier 3 line, so a $9,001 reduction in MAGI, such as a qualified charitable distribution, would save about $1,460 a year.
Single filer, MAGI $500,000: tier 5, premium $689.90, surcharge $487 a month or $5,844 a year.
Using it for planning
Plan income two years ahead: conversions at 63 affect premiums at 65. Leave a buffer under each line because future thresholds are adjusted for inflation and you won't know them in advance. If income fell because of retirement or another life-changing event, Form SSA-44 can ask SSA to use a more recent year. More in Part B premiums and IRMAA.
Not modeled: Part D IRMAA, married filing separately, appeals, and future-year thresholds.
Common IRMAA surprises
- Capital gain distributions from mutual funds in taxable accounts arrive in December and can push you over a line you thought you'd avoided.
- Home sales with gains above the exclusion count in full.
- Municipal bond interest is tax-free for income tax but included in IRMAA MAGI.
- The survivor year. A widow or widower filing single faces thresholds half as high as joint filers.
Check the calculator before year-end decisions, not after.
FAQ
What income does IRMAA use?
Modified adjusted gross income, meaning AGI plus tax-exempt interest, from the tax return two years before the premium year. 2026 premiums use 2024 income.
Is IRMAA charged per person?
Yes. Each person on Part B pays the surcharge, so a married couple in a surcharge tier pays it twice.
Does the calculator include Part D IRMAA?
No. Part D surcharges follow the same income tiers and are added to your drug plan premium separately.
Can I lower IRMAA after retiring?
If your income dropped because of a life-changing event such as stopping work, you can ask SSA to use more recent income with Form SSA-44.
Are the IRMAA thresholds adjusted for inflation?
Yes, the income thresholds are generally indexed each year, except the top tier. Because premiums use income from two years earlier, you won't know the exact thresholds that apply when you earn the income, so leave a buffer below each line when you plan conversions or sales.
Sources & fact-check notes
- CMS fact sheet: 2026 Medicare Parts A & B premiums and deductibles (accessed 2026-10-25)
Figures checked October 25, 2026. Rules and limits change; verify with the official source before acting.