RetirementEquation
Sources

Every document we cite

Each figure on this site traces to one of the documents below. We cite CMS, SSA and the statute directly, not another blog, broker or comparison site. Why that rule exists.

IRMAA — Medicare income surcharges

YearDocumentPublishedProvides
2026CMS Medicare Parts A & B premiums and deductibles, 20262025-11-14Standard premium, MAGI brackets, Part B and Part D IRMAA amounts
2025CMS Medicare Parts A & B premiums and deductibles, 20252024-11-08Standard premium, MAGI brackets, Part B and Part D IRMAA amounts
2024CMS Medicare Parts A & B premiums and deductibles, 20242023-10-12Standard premium, MAGI brackets, Part B and Part D IRMAA amounts
2024Federal Register: Part B monthly actuarial rates and premiums, 20242023-10-17The rulemaking notice behind the CMS fact sheet for this year
2024CMS Part D national average bid, 20242023-07-31Part D national base beneficiary premium for this year
2023CMS Medicare Parts A & B premiums and deductibles, 20232022-09-27Standard premium, MAGI brackets, Part B and Part D IRMAA amounts
2023Federal Register: Part B monthly actuarial rates and premiums, 20232022-09-29The rulemaking notice behind the CMS fact sheet for this year
2023CMS Part D national average bid, 20232022-07-29Part D national base beneficiary premium for this year
2027CMS Part D national average bid, 20272026-07-28Part D base premium only — no brackets or Part B figures published yet
Standing referenceProvides
SSA POMS HI 01101.020The IRMAA sliding-scale tables and the interval rules for each tier
SSA POMS HI 01101.031How IRMAA is calculated, including the Part B cost-share percentages
SSA POMS HI 01101.010The definition of MAGI and which tax year applies
Social Security Act §1839(i), 42 U.S.C. §1395r(i)The statute itself, including how the MAGI thresholds are indexed
Form SSA-44The life-changing-event form used to request a reduction

How these are used: IRMAA methodology.

Late enrollment penaltiesplanned

Part B and Part D late-enrollment penalties, and the forms that establish a Special Enrollment Period.

Standing referenceProvides
CMS Form L564 / CMS-40BEmployment verification and Part B enrollment forms

What we do not cite

Brokers, comparison sites and finance media all publish versions of these figures, and most are copied from the documents above. Copying a copy is how an error spreads and outlives its correction — so we go to the source and tell you which one.

Where a figure here does not match the document beside it, the document is the one to trust. Let us know and we will correct the page.