Guides
Every guide is checked against Social Security, CMS and Medicare publications, with the sources listed at the bottom.
Signing up for Part B after employer coverage
- The Part B Special Enrollment Period: who qualifies and how the 8 months work
The Part B Special Enrollment Period gives you 8 months after your job or job-based coverage ends, whichever is first. Who qualifies and how to count them.
- How to fill out CMS-L564: Section A and Section B, line by line
How to fill out CMS-L564 (Revised 03/2025): what you write in Section A, what your employer completes in Section B, the signature rules, and tips for HR.
- Employer won't (or can't) sign CMS-L564? What Social Security accepts instead
Employer won't complete Section B of CMS-L564, is too slow, or went out of business? Here is the other proof of job-based coverage Social Security accepts.
- CMS-40B instructions: how to fill out the Part B enrollment request
CMS-40B (07/2025) step by step: who can use it, Section 1 basics, the four questions in Section 2, choosing your Part B start date, and signing Section 3.
- COBRA and Medicare Part B: why COBRA doesn't extend your deadline
COBRA never counts as coverage from current work, so it doesn't extend your 8-month Part B window. A worked example, and what to do if you're already on COBRA.
- The Part B late enrollment penalty: how it's counted, with worked examples
How the Part B late enrollment penalty is counted: 10% per full 12 months, which months count, why job-coverage months don't, and 2026 examples at $202.90.
- When does Part B start if you sign up during the Special Enrollment Period?
When Part B starts depends on when you sign up: while still covered, in the first full month after, or later in your 8-month window. Rules and dated examples.
- How to submit CMS-40B and CMS-L564: online, by fax, by mail or in person
How to send your Part B Special Enrollment forms to Social Security: online, by fax, by mail or in person, plus what to keep and when to send them.
- Retiree health coverage and Medicare Part B: why it doesn't let you wait
Retiree coverage from a former employer isn't coverage from current work. Medicare usually pays first, and your 8-month Part B window starts when the job ends.
- Working past 65 at a small employer: Medicare pays first, but you still get the SEP
With fewer than 20 employees, Medicare pays first and your job plan may not pay without Parts A and B. The Part B Special Enrollment Period still applies.
IRMAA and form SSA-44
- How IRMAA is calculated: MAGI, the 2-year lookback and the tiers
IRMAA uses your MAGI from two years back: AGI (1040 line 11) plus tax-exempt interest (line 2a). How 2026 tiers, cliffs and Part D add-ons work, with examples.
- IRMAA brackets 2026: the full Part B and Part D tables
Official 2026 IRMAA brackets for single, joint and married-filing-separately filers, based on 2024 MAGI. Part B runs $202.90 to $689.90, plus Part D add-ons.
- IRMAA brackets 2027: what's known so far
The 2027 IRMAA brackets aren't out yet. What's known: they use 2025 tax returns, limits rise with inflation, and when Social Security will show your premium.
- How to fill out SSA-44 step by step
Plain-English SSA-44 instructions for the 12-2025 form: which event to check, which tax year to use, the MAGI lines, evidence, signing and how to submit it.
- SSA-44 for retirement: using the work stoppage event to lower IRMAA
Retired, but IRMAA still reflects your working years? How SSA-44's work stoppage event works: what counts, the proof SSA accepts, timing and a worked example.
- Got an IRMAA letter? What it means and what to do
Your IRMAA notice is a Social Security decision you can act on. How to check the tax year and MAGI it used, and your options: SSA-44, an IRS fix or an appeal.
- IRMAA life-changing events: the 8 that qualify, and what doesn't
The 8 life-changing events Social Security accepts to lower IRMAA, what doesn't count (capital gains, IRA conversions, market losses) and the proof for each.
- IRMAA appeal vs. SSA-44: which one do you need?
SSA-44 asks for a new IRMAA decision after a life-changing event. An appeal (SSA-561-U2) challenges the decision within 60 days. When to use each, or both.