The countdown
Turning 65: the Medicare checklist, month by month
Short answer: your Initial Enrollment Period is 7 months long, centered on your 65th birthday month, and enrolling in the 3 months before your birthday month gives you coverage the month you turn 65 with no gap. Here’s the whole countdown as a timeline: what to do at 64, what to do each month of the window, and which deadlines bite permanently if missed.
Key takeaways
- Your Initial Enrollment Period runs 7 months: 3 months before your 65th birthday month, your birthday month, and 3 months after.
- Enroll during the first 3 months and coverage starts the month you turn 65, gap-free.
- Still working with 20+ employees? You can delay penalty-free, but verify it in writing and mind the HSA rule.
- Your 6-month Medigap window opens when Part B starts and never repeats; it’s the decision with the longest consequences.
- Missing the window without qualifying coverage costs 10% per 12 months on Part B, permanently.
Six or more months before 65: the setup
- Confirm your dates. Your 7-month window is anchored to your birthday month. (Quirk worth knowing: born on the 1st, and Medicare treats you as turning 65 the prior month, shifting everything a month earlier.)
- Decide the work question. Retiring by 65, or working on? If working with employer coverage, get the 20-employee answer from HR in writing now, because it determines your entire strategy.
- Stop HSA contributions on schedule if applicable. Enrolling in any part of Medicare ends HSA eligibility, and Part A can backdate up to 6 months. The clean move: stop contributions about 6 months before your intended enrollment.
- Inventory your doctors and drugs. This list is the raw material for every decision that follows; ten minutes now saves hours in the window.
The window itself
| When | What happens | Your move |
|---|---|---|
| 3 months before birthday month | IEP opens | Enroll in A and B at ssa.gov; coverage starts the month you turn 65 |
| 2 months before | Best decision month | Choose your path: Original + Medigap + Part D, or Advantage |
| 1 month before | Cards and confirmations arrive | Verify effective dates; pick drug plan if not done |
| Birthday month | Coverage active (if enrolled early) | Medigap window opens with Part B; book the "Welcome to Medicare" visit |
| Months +1 to +3 | IEP still open, but… | Enrolling now delays your coverage start; don’t coast here |
| Month +6 after Part B | Medigap window closes | Last day of guaranteed-issue supplement pricing |
Initial Enrollment Period structure per SSA and Medicare.gov; enrolling before the birthday month prevents any coverage gap.
Inside the window: the decision, in order
- Enroll in A and B at ssa.gov/medicare; the online application takes most people about 15 minutes. This step is nearly universal (the exception is the still-working case below, and even then most people take free Part A unless an HSA says otherwise).
- Pick your path. The doctors/health/budget/travel framework is laid out in the comparison, or answer nine questions in the decoder and get a reasoned recommendation.
- If Original Medicare: buy the Medigap plan inside your 6-month window. This is the single decision on the whole checklist that can’t be cleanly redone later; underwriting waits outside the window in most states. The G-vs-N choice is arithmetic, and we did it.
- Add drug coverage either way: a stand-alone Part D plan next to Original Medicare, or built into your Advantage plan. Even on zero medications, a cheap plan stops the permanent 1%-per-month penalty clock.
After enrolling: the mop-up list
- Store your Medicare number safely and give the new coverage details to every provider’s office.
- Schedule the free "Welcome to Medicare" preventive visit within your first 12 months.
- Set two recurring calendar notes forever: September (read the Annual Notice of Change) and October 15 to December 7 (re-shop if it moved against you).
- If your income just dropped at retirement and you’re being IRMAA-surcharged, file form SSA-44.
The parallel track: still working at 65
Employer coverage from 20 or more employees: you may delay Part B penalty-free, keep the employer plan, and get an 8-month Special Enrollment Period when work ends, at which point your Medigap window starts fresh with the delayed Part B. Most people in this lane still take free Part A, unless HSA contributions argue otherwise. Employer under 20: Medicare becomes primary at 65 whether you enrolled or not, so enroll on time. Either way, the answers belong in writing; the full rules live in our working-past-65 guide.
The one-sentence version of this entire page: enroll in the 3 months before your birthday month, choose your path deliberately, and treat the 6-month Medigap window as the deadline it is. Everything else is logistics.
Questions people also ask
When should I sign up for Medicare if I’m turning 65?
During the 3 months before your 65th birthday month, which makes coverage start the month you turn 65 with no gap. Your full Initial Enrollment Period spans 7 months (3 before, birthday month, 3 after), but enrolling in the later months delays your start date.
What happens if I miss my Initial Enrollment Period?
Without qualifying employer coverage, you wait for the next General Enrollment window and pay a permanent Part B penalty of 10% for every 12 months you were late, plus a Part D penalty of 1% of the national base premium per month without creditable drug coverage.
Do I need to sign up for Medicare at 65 if I’m still working?
If your coverage comes from current employment at an employer with 20 or more employees, you can delay Part B penalty-free and enroll within 8 months of that coverage ending. Under 20 employees, Medicare is primary at 65 and you should enroll on time. Get the employer-size answer in writing.
When can I buy a Medigap plan?
Your guaranteed window is the 6 months starting when your Part B coverage begins (at 65 or older). During it, every insurer must sell you any plan at standard rates with no health questions. It does not repeat, and outside it most states allow medical underwriting.
Does Medicare start automatically at 65?
Only if you’re already receiving Social Security benefits, in which case A and B start automatically your birthday month. Otherwise you must actively enroll through Social Security.
Sources for this article
- SSA.govSign up for Medicare: the enrollment application and timing rules.
- Medicare.govBuying a Medigap policy: the 6-month window that anchors the checklist’s biggest deadline.
- CMS.gov2026 premiums and deductibles: the cost figures behind the path decision.
Figures checked against these sources in July 2026. We update within weeks when CMS publishes new amounts.