IRMAA brackets 2027: projection from the law’s own formula

2027 Medicare premiums will depend on your 2025 MAGI. CMS has not published the 2027 table yet. The thresholds, though, follow a fixed formula tied to the CPI-U, and all the data it needs (through August 2026) is out. Result: the first bracket should start above $112,000 (individual) and $224,000 (joint), against $109,000 and $218,000 in 2026.

Projected 2027 IRMAA thresholds (MAGI in 2025)
Tier starts above	2026 (official)	2027, October skipped	2027, October interpolated	Joint 2027	Confidence
Tier 1	$109,000	$112,000	$112,000	$224,000	Same under both methods
Tier 2	$137,000	$142,000	$141,000	$282,000 or $284,000	Depends on the October 2025 gap
Tier 3	$171,000	$177,000	$176,000	$352,000 or $354,000	Depends on the October 2025 gap
Tier 4	$205,000	$212,000	$211,000	$422,000 or $424,000	Depends on the October 2025 gap
Tier 5 (from)	$500,000	$500,000	$500,000	$750,000	Fixed by law until 2027
Married filing separately, tier 5 from	$391,000	$388,000	$388,000	—	$500,000 minus the tier-1 threshold

Test your 2025 income against the 2027 projection

The formula

Social Security Act §1839(i)(5) takes the dollar amounts written in the law for 2019 onward — $85,000, $107,000, $133,500, $160,000 — and multiplies each one by the growth of the CPI-U (all urban consumers, U.S. city average) between two 12-month periods ending in August:

base: September 2017 to August 2018, average 249.280;
for 2027: September 2025 to August 2026, average 329.656 on the 11 published months, or 329.223 with October interpolated.

Each result is rounded to the nearest $1,000. Joint thresholds are twice the individual ones. Unrounded 2027 values (October skipped / interpolated):

$85,000 → $112,407 / $112,259 → rounded $112,000 / $112,000
$107,000 → $141,500 / $141,314 → rounded $142,000 / $141,000
$133,500 → $176,545 / $176,313 → rounded $177,000 / $176,000
$160,000 → $211,589 / $211,311 → rounded $212,000 / $211,000

Look at tier 2: the 11-month version lands at $141,500.31, a few cents from the halfway point that decides between rounding down to $141,000 and up to $142,000. Small differences in method flip the result, which is why only tier 1 is certain.

Checked against every published year

Run on BLS data, the same formula gives exactly the thresholds CMS published for each premium year from 2020 to 2026 — all four individual thresholds, every year. The check runs automatically each time this site is rebuilt.

The missing October 2025

The BLS data series carries this note for October 2025: “Data unavailable due to the 2025 lapse in appropriations”. The law says “the average … for the 12-month period”; it does not say what to do if one month has no value. We have not found an official statement on how CMS will fill the gap. When CMS publishes the 2027 table (the last seven releases came between September 27 and November 14), this page will switch to the official numbers.

What the projection means for you

If your 2025 MAGI is below $112,000 (individual) or $224,000 (joint), you should not owe IRMAA in 2027 on that income.
If you are within about $1,000 of the tier-2, tier-3 or tier-4 threshold, wait for the official table before drawing conclusions.
For 2026 income (2028 premiums), the thresholds will move again, and the top thresholds will be indexed for the first time since 2019.

Frequently asked questions

Is this the official 2027 table?

No. CMS has not published it yet (checked September 29, 2026). This is the result of the indexing formula in Social Security Act §1839(i)(5), applied to CPI-U data the Bureau of Labor Statistics has already published. The same formula reproduces every published threshold from 2020 to 2026 to the dollar; our test suite checks it.

Why two versions?

The formula averages the CPI-U over the 12 months from September 2025 to August 2026. The BLS never published October 2025 because of the 2025 lapse in appropriations. We have not found an official statement on how CMS will fill that gap, so we compute both reasonable options: an 11-month average, and October estimated as the midpoint of September and November. The calculator uses the lower threshold of the two, the cautious choice if you are trying to stay under a bracket.

What about the 2027 premium amounts?

They cannot be projected from public data: they depend on the Medicare actuaries’ cost estimate for Part B and on the Part D base beneficiary premium. Our tools show 2027 brackets with 2026 dollar amounts and say so. Premiums have risen in most recent years (Part B: $185.00 in 2025, $202.90 in 2026), so 2027 surcharges will probably be higher, not lower.

Will the $500,000 and $750,000 top thresholds change?

Not for 2027. The law froze them and starts indexing them in 2028, using the CPI-U change from the 12 months ending August 2026.

Which income counts for 2027?

Your 2025 MAGI, from the tax return you filed in 2026. If the year is already closed, IRMAA planning for 2027 is about checking where you landed, and whether a life-changing event lets you ask SSA to use 2026 or 2027 income instead.

Official sources

Sources read on September 29, 2026. Consumer Price Index data downloaded from the BLS on September 29, 2026.

Page updated September 29, 2026. Official figures checked against CMS and SSA on September 29, 2026.