Guides

Short, plain-language explainers on the timing rules behind the checker. They cover the arithmetic and the common gotchas; none of them recommend a plan or an insurer.

• Late-enrollment penalty calculator (Part B & Part D)

  Enter the months you went without Part B or creditable drug coverage and see your permanent monthly, annual, and lifetime penalty — including why an 11-month Part B gap costs nothing.

• The turning-65 enrollment timeline, explained

  How the 7-month Initial Enrollment Period is built, when coverage actually starts, and the first-of-the-month birthday rule that shifts everything a month earlier.

• Working past 65 and the Part B Special Enrollment Period

  When you can safely delay Part B with employer coverage, the eight-month window that opens when that coverage ends, and the traps (COBRA and retiree plans) that do not count.

• Late-enrollment penalties, with worked dollar examples

  The Part B 10-percent-per-year formula and the Part D 1-percent-per-month formula, worked out in real dollars, and why they last for life.

• The Part B premium and IRMAA in 2026

  How the standard Part B premium works, how the income-related surcharge (IRMAA) stacks on top for higher earners, which tax year Social Security uses, and worked example figures.

• The Medigap open enrollment window and guaranteed-issue rights

  The one-time, six-month window to buy a Medicare Supplement policy without medical underwriting, plus the guaranteed-issue rights that can offer a second chance later.

• Medicare Advantage vs Original Medicare: how timing differs

  The shared entry deadline, the different calendars for changing plans afterward, and the trial rights that let first-year Advantage members switch back to Original Medicare.

• The Annual Election Period, explained

  What you can change during the October 15 to December 7 window, how it differs from the January 1 to March 31 Medicare Advantage open enrollment period, and a step-by-step fall review.

• The Part D penalty and what counts as creditable coverage

  How the lifelong Part D late-enrollment penalty is calculated, what qualifies as creditable drug coverage that protects you, and worked examples of the monthly surcharge.

• When Medicare enrollment is automatic

  Why drawing Social Security before 65 enrolls you in Part A and Part B automatically, what arrives in the mail, when to decline Part B, and who must still sign up manually.

• The General Enrollment Period: the January-to-March fallback

  Who ends up needing Medicare's once-a-year fallback window, the 2023 rule change that starts coverage the month after you sign up, how the penalty attaches at enrollment, and the exceptional-circumstance SEPs to check first.

• Medicare and COBRA: two clocks, and only one is kind

  Why COBRA never extends the eight-month Part B window, why its drug coverage can still satisfy the 63-day Part D rule, and how the primary-payer rules can leave COBRA paying almost nothing after 65.