Medicare IRMAA Calculator

How to use

1. 01

   Enter the modified adjusted gross income from your tax return of two years ago, not this year's. Social Security asks the IRS for the return two years before the premium year, so a 2026 premium is set by what you reported for 2024. Modified AGI here is your adjusted gross income plus any tax-exempt interest, which catches municipal bond income that is invisible on the AGI line itself.

2. 02

   Say whether one or two people on that return are enrolled in Medicare. The income thresholds double for a joint return, but the surcharge is charged per enrolled person, so a couple who both have Part B pay it twice. That is why the headline figure says 'both people' when you enter 2.

3. 03

   Read the bracket first. Standard means no surcharge at all; anything from 1 to 5 of 5 means the surcharge applies, and the page shows how far past that bracket's threshold you landed. The brackets are steps, not a slope, so the distance past the threshold is what tells you whether a small change would have avoided the whole thing.

4. 04

   Check the distance to the next threshold before you plan any income for the current year. The figure the page shows is how much more income would move you up an entire step — and because a step costs the same whether you cross it by a dollar or by twenty thousand, that distance is the real budget for a Roth conversion, a capital gain or a property sale.

5. 05

   Read the Part D line separately. It is charged on top of whatever your drug plan already costs and is collected by Medicare rather than by the plan, so the premium a Part D plan advertises is not the whole bill at this income. Open Advanced options if you want to override the standard Part B premium with a different year's figure.

Formula

The page looks your modified AGI up in the 2026 Part B bracket table and takes the bracket index, using the joint thresholds when two people are on the return. The boundaries are not uniform: every bracket but the last two is 'greater than X and less than or equal to Y', the fifth is 'greater than $205,000 and less than $500,000', and the sixth is 'greater than or equal to $500,000', so exactly $500,000 single or $750,000 joint falls in the top bracket rather than the one below. The same index then reads the Part D surcharge, because both tables share one set of income bands. The surcharge per person = the Part B surcharge + the Part D surcharge. The household's monthly cost = that figure × the number of people enrolled, and the annual cost is twelve times the monthly. Your full Part B premium = the standard premium of $202.90 + the Part B surcharge. The saving from dropping one bracket = (this bracket's combined surcharge − the previous bracket's) × 12 × the number of people enrolled.

Example

A single filer reported $130,000 of modified AGI on the 2024 return, and that return sets the 2026 premium. It falls in bracket 1 of 5, $21,000 past the $109,000 threshold. Part B carries an $81.20 monthly surcharge, taking the premium from the standard $202.90 to $284.10; Part D carries $14.50, charged on top of whatever the drug plan itself costs. Together that is $95.70 a month and $1,148 for the year, and the next threshold is $7,000 away at $137,000. Drop the same filer to $107,000 and the bracket is Standard, the surcharge is $0.00 and Part B is the plain $202.90 — $1,148 a year saved on $23,000 less income. At the other end, $499,000 puts the filer in bracket 4 at $529.60 a month, and $500,000 exactly crosses into the top bracket at $578.00 a month, so the last $1,000 of income costs $581 for the year. A couple filing jointly at $300,000 with both enrolled sit in bracket 2, paying $202.90 and $37.50 each per month, which comes to $480.80 a month and $5,770 across the household.

Definitions

Modified AGI (from 2 tax years ago)

Adjusted gross income plus tax-exempt interest, taken from the return two years before the premium year. The 2024 return sets the 2026 premium.

People on that tax return

How many people covered by that return are enrolled in Medicare — 1 or 2. Joint thresholds are double the single ones, but the surcharge is billed per enrolled person.

IRMAA

Income-Related Monthly Adjustment Amount: the extra premium Medicare charges higher-income beneficiaries on Part B and Part D. It is an addition to the premium, not a tax.

Standard Part B premium

What everyone below the first threshold pays — $202.90 a month for 2026 under the CMS annual determination. An advanced input, so you can price a different year.

Part B surcharge

The amount added to each enrolled person's Part B premium by their bracket, from $81.20 at the first step to $487.00 at the top.

Part D surcharge

A separate addition on the same income bands, from $14.50 to $91.00. Medicare collects it directly rather than through your drug plan, so it sits on top of the plan's own premium.

Bracket

Which of the six income bands you fall in, shown as Standard or as 1 through 5 of 5. Crossing a boundary by one dollar applies the whole step.

Form SSA-44

The form that asks Social Security to reconsider an IRMAA determination after a life-changing event such as retirement, divorce or the death of a spouse reduced your income.

Frequently asked questions