The short answer
The IRMAA cliff means the surcharges are fixed steps. Land one dollar of MAGI over a 2026 bound like 109,000 dollars individual, and the full next-step surcharge applies for the premium year, 95.70 dollars a month at the first crossing by arithmetic on the government's own tables.
Plan year 2026. Every figure on this page is the 2026 value or arithmetic derived from it, read from Social Security's higher-income chart and CMS's 2026 fact sheet on August 7, 2026. The bracket map changes on a yearly cycle, and this page tracks the current plan year only.
Say your income lands one dollar over a line. You do not pay a proportion of that dollar. You pay the whole step, the same as somebody ten thousand dollars past it, and the last dollar you earned becomes the most expensive one of your year.
What is the IRMAA cliff?
The IRMAA cliff is the all-or-nothing shape of the brackets: surcharges arrive as fixed steps, not gradual slopes, so a single dollar of MAGI over a bound triggers the bracket's full monthly amount. Call it the One Dollar Step: the smallest possible overshoot buys the entire stair.
The One Dollar Step is arithmetic on the government's own 2026 tables, which attach one fixed Part B addition and one fixed Part D addition to each MAGI row, with no gradation inside a row. The tables are the government's. The arithmetic and the naming are ours.
Nothing about the cliff is hidden: the bounds are published, the additions are published, and the edge between any two steps is exactly one dollar wide.
What happens if I go one dollar over a bracket?
One dollar over a bracket bound moves you to the next step for the whole premium year: the surcharge is set by which MAGI row your return lands in, never by how far into the row it lands. The table reads above, and above by one dollar counts.
The row language is Social Security's own: each 2026 rung is phrased as MAGI above one figure up to the next, so the boundary test is binary. Inside a row, every MAGI pays the same additions.
Both surcharges move together on the shared ladder, so a crossed bound raises the Part B addition and the Part D addition in the same premium year.
How much does crossing a bracket cost?
Crossing the first 2026 bound costs 95.70 dollars a month, derived from the government's 2026 tables: the first Part B addition of 81.20 plus the first Part D addition of 14.50, and a full premium year at that step totals 1,148.40 dollars.
The 95.70 and 1,148.40 figures are this publication's arithmetic on those published additions, not numbers the government prints. The components are checkable on Social Security's chart; the sums are ours.
Higher crossings cost more per step. The second 2026 rung carries additions of 202.90 for Part B and 37.50 for Part D, so the step from rung one to rung two raises the combined monthly surcharge from 95.70 to 240.40 dollars, again by derived arithmetic on the published additions.
Three of those crossings cost within ten cents of each other. Subtracting each rung's combined total from the one below it gives 95.70, then 144.70, 144.60, 144.60 and 48.40 dollars in 2026. The middle three are the same step to within a dime, and that is derived arithmetic on the published additions rather than a figure Social Security states.
Here is what each crossing adds, in 2026, on both parts at once.
| The rung you cross | Added to Part B | Added to Part D |
|---|---|---|
| First, above 109,000 individually | 81.20 dollars | 14.50 dollars |
| Second, above 137,000 | 202.90 dollars | 37.50 dollars |
| Third, above 171,000 | 324.60 dollars | 60.40 dollars |
| Fourth, above 205,000 | 446.30 dollars | 83.30 dollars |
| Fifth, 500,000 and above | 487.00 dollars | 91.00 dollars |
Every figure in that table is a 2026 plan year amount, and every one applies in full from the first dollar over the line. There is no partial rung. Only the crossing matters, not the distance you cross by.
The asymmetry against ordinary tax logic is the point to carry: brackets in the income tax slope within the crossing; these do not.
Where are this year's bracket breakpoints?
The 2026 breakpoints for individual filers sit at MAGI of 109,000, 137,000, 171,000, 205,000, and 500,000 dollars, per Social Security's chart, with joint bounds of 218,000, 274,000, 342,000, 410,000, and 750,000. Married filing separately runs its own two tier structure above the entry threshold.
MAGI is measured as total adjusted gross income plus tax-exempt interest income, generally from the return two years before the premium year, which is why the crossing that matters in 2026 already happened, on the 2024 return.
The map is republished each year, and the determination letter names the row your return landed in, so the check against the chart takes one line.
How do I stay under the next bracket?
Staying under a bracket is a MAGI arithmetic problem: the measure is adjusted gross income plus tax-exempt interest, generally from the return two years before the premium year. What the arithmetic allows, and which moves fit your situation, is planning territory that belongs to you and a tax professional.
What the published record does say: income counts in the year it lands, including amounts converted to a Roth IRA, which the IRS includes in gross income for the conversion year. The timing mechanics of that specific move fill the companion Roth conversion article.
The other structural fact is humility about the future: the bounds are published year by year, so the bracket a future year's income will meet is not knowable in advance. Planning happens against the current map, and the map moves.
Can I appeal if I crossed a bracket by accident?
An accidental crossing is only correctable on defined paths: the determination follows the return, so relief requires a life-changing event on Social Security's list, an amended return, or wrong IRS data. Overshooting a bound through ordinary income, however narrowly, is not on the relief list.
The three paths are specific. A listed life-changing event, filed on form SSA-44 with proof. An amended return, shown with its IRS acknowledgment, which corrects or removes the adjustment. And a MAGI figure the IRS reported wrongly, corrected with the IRS itself.
Reading the list against the accident case is sobering: the relief machinery answers changed lives and wrong records, never near-misses. Prevention, in this one corner of Medicare, is the only complete remedy the rules describe.
What changed this year
The thresholds on this page are 2026 plan year values, and moving a threshold moves the cliff with it. The first line rose, the top surcharge rose, and the size of each step is set for the plan year rather than fixed. Every figure below names its year.
The first line is 109,000 dollars on an individual return and 218,000 dollars on a joint return in 2026, up from 106,000 dollars and 212,000 dollars in 2025. A dollar over that line still costs the whole first step, and the step itself is larger: 81.20 dollars a month for Part B in 2026.
The final cliff is bigger too. The top Part B adjustment is 487.00 dollars a month in 2026 against 443.90 dollars in 2025, and the top Part D adjustment is 91.00 dollars against 85.80 dollars.
Source: the CMS fact sheets of November 14, 2025 and November 8, 2024.
What this means for you
The cliff is the brackets' defining shape: five fixed steps, full price per step, one dollar of MAGI enough to change floors for a premium year. The map is published fresh each year, the measuring happens two years early, and the relief list never includes simply having missed by a little.
For the full ladder, the brackets article. For the delay, the lookback article. For the one move people most often time around the steps, the Roth conversion article beside this one.
FAQ
Is IRMAA marginal like income tax brackets?
No, and expecting the familiar bracket behavior, where crossing a line touches only the dollars past it, is the single most expensive misunderstanding in the subject.
The IRMAA table is a step function: Social Security's chart attaches one fixed Part B addition and one fixed Part D addition to each MAGI row, and landing anywhere in a row, by one dollar or by twenty thousand, prices the entire row.
In 2026 the first crossing adds 81.20 dollars a month for Part B and 14.50 for Part D. Nothing prorates. The mental model that works is a stair, not a ramp, and the edge of every stair in the 2026 map is exactly one dollar wide.
How much more does the second bracket cost than the first?
By this publication's arithmetic on the government's 2026 additions, the first rung's combined surcharge is 95.70 dollars a month, from 81.20 for Part B plus 14.50 for Part D. The second rung's is 240.40, from 202.90 plus 37.50. The step between the rungs is therefore 144.70 dollars a month in 2026, which is larger than the entire first surcharge.
The published components are on Social Security's chart; the sums are derived. The pattern holds up the ladder: each rung's additions exceed the last's, so the cost of a crossing grows with altitude, and the top rung in 2026 carries additions of 487.00 and 91.00 dollars.
Do the bracket bounds change every year?
The map is published per year, and this page quotes only the 2026 edition: individual bounds at 109,000, 137,000, 171,000, 205,000, and 500,000 dollars of MAGI, joint bounds from 218,000 up to 750,000. Nothing on the pages this article draws from states future bounds, and this publication does not project them.
That yearly refresh matters most to planners, because income earned now meets the bracket map of two years from now, a map nobody has seen. The reliable habits are checking the current chart on Social Security's page, and reading the year label on any bracket table before trusting it, including this one.
Does the cliff hit Part B and Part D at the same time?
Yes, when you hold both coverages. The two surcharges hang on one ladder: a single MAGI, from one tax return, sets your row, and Social Security applies the adjustment to each coverage you have, stated in its own letter.
So a crossed bound in 2026 raises the Part B addition and the Part D addition together, which is why the crossing arithmetic on this page always sums the pair. Hold only one coverage and only that one carries the adjustment, with the other applied automatically if you enroll later the same year.
One ladder, two riders, one letter. They ride the same brackets. The 2026 Part B surcharges (G7) and the 2026 Part D additions (G8) are keyed to the identical MAGI thresholds (G4), so crossing one line moves both.
My MAGI was barely over. Is there any relief for a near miss?
Not for the near miss itself. The relief machinery has three doors, and all three are about the record, not the margin. A life-changing event from Social Security's list, filed on form SSA-44 with documentation; an amended return, shown with its IRS acknowledgment receipt; or a MAGI figure the IRS transmitted wrongly, corrected with the IRS.
An accurate return that lands one dollar into a row prices that row, and nothing in the published record offers a rounding allowance. That hard edge is exactly why the planning articles beside this one exist: the arithmetic can only be influenced in the earning year, never in the premium year.
