The numbers behind the window
Here's what to do, in 4 steps.
Four steps. The first is figuring out your seven-month window — that's the math, no judgment. The next two depend on whether you're already drawing Social Security. The fourth is the trap-spotter: if you have employer coverage at sixty-five, slow down before you auto-enroll in Part B.
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Find your Initial Enrollment Period
Three months before, the month of, and three months after your sixty-fifth birthday. That's the seven-month window. Mark the start date on a calendar — most people miss it because they treat it as a single date instead of a window.
Time: 5 minutes Cost: Free Medicare basics — get started
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If you're already on Social Security, watch the mail
If you're drawing Social Security or Railroad Retirement at sixty-five, you're auto-enrolled in Part A and Part B. Your Medicare card arrives by mail roughly three months before your birthday. You don't have to do anything to start coverage — but you do have to decide whether to keep Part B if you have other creditable coverage.
Time: Passive Cost: Free Medicare via SSA
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If you're not on Social Security, apply at ssa.gov/medicare
Most people qualify for premium-free Part A based on their own or a spouse's work history (forty-plus quarters of Medicare-covered employment). Part B carries a monthly premium. The application is online and the agency handles both Parts in a single filing.
Time: 15 minutes Cost: Free to apply SSA Medicare enrollment
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Check whether you need a Special Enrollment Period
If you have active employer health coverage at sixty-five and the employer has twenty or more employees, you may be able to defer Part B without penalty using the working-aged SEP. Smaller employers don't qualify the same way — Medicare becomes primary at sixty-five. Don't auto-enroll without checking. The wrong move here is what triggers the lifetime late-enrollment penalty.
Time: 30 minutes Cost: Free Medicare basics — get started
Dr. Ed walks through the seven-month Medicare window
Video coming soon
I'm filming the Medicare enrollment walkthrough — the auto-vs-active distinction, the working-past-sixty-five trap, and what to do if you missed your IEP. Drop your email and I'll send it the day it goes live.
Which of these sounds more like you?
Most readers land here in one of two situations: turning sixty-five and not yet on Social Security, or turning sixty-five and already drawing it. The path is different. Pick the one that sounds like you and the rest of the page gets simpler.
I'm turning 65 and I'm not getting Social Security yetYou'll need to actively enroll — there's no auto-pilot
If you haven't filed for Social Security yet, you are not auto-enrolled in Medicare. The agency doesn't know you turned sixty-five for Medicare purposes the same way it does once you've filed. You apply at ssa.gov/medicare during your seven-month Initial Enrollment Period.
Most people qualify for premium-free Part A based on their own or a spouse's work history (forty-plus quarters of Medicare-covered employment). Part B carries a monthly premium. Both are handled in a single online application.
Doing this in the three months before your birthday — not after — is the cleanest path. Coverage starts the month after you enroll.
If you're already drawing Social Security, the next card down is yours. → See enrollment periods explained
I'm turning 65 and I'm already on Social SecurityYou'll be auto-enrolled — watch the mail
If you're already drawing Social Security or Railroad Retirement at sixty-five, you're auto-enrolled in Part A and Part B. The Medicare card arrives by mail roughly three months before your birthday.
The one decision you have to make is whether to keep Part B. If you have other creditable coverage — most commonly a current employer's group plan that meets Medicare's standard — you can decline Part B and pick it up later under a Special Enrollment Period without a late-enrollment penalty. Form CMS-1763 is the formal Part B disenrollment.
If you're declining Part B, do it before the Part B effective date on the card. After that, the penalty math gets more complicated.
If you're declining Part B because you're still working, the next card is the one you want. → See working past 65
I'm still working at 65 with employer health insuranceDon't auto-enroll without checking the rules first
This is the highest-stakes decision on this page. The wrong move triggers a late-enrollment penalty for life.
The rule turns on employer size. If your employer has twenty or more employees, your group plan is generally primary and you may defer Part B without penalty using the working-aged Special Enrollment Period. If the employer has fewer than twenty employees, Medicare typically becomes primary at sixty-five and your group coverage pays second — enrolling in Part B during your IEP is usually the right call.
Before you make the call, get the employer's coverage details in writing and run them past SHIP at one-eight-seven-seven, eight-three-nine, two-six-seven-five. Free, unbiased, and they do this every day.
Want the full working-past-65 walkthrough? → See working past 65 with employer coverage
I missed the month of my birthday — am I in troubleProbably not. The IEP is a window, not a deadline at the birthday
Take a breath. The Initial Enrollment Period is seven months long. You still have three months after your birthday month inside the IEP to enroll without penalty.
Even if your IEP closes, you're not stuck. The General Enrollment Period runs January first through March thirty-first each year for people who missed their IEP and don't qualify for a Special Enrollment Period. If you have a qualifying event — most commonly losing creditable employer coverage — a Special Enrollment Period can give you eight months without a late-enrollment penalty.
The penalty risk goes up the longer you wait, but missing the exact birthday is not the trap most people think it is.
Want all the enrollment periods explained side by side? → See Medicare enrollment periods
I'm enrolled in Part A — do I need Part B tooUsually yes — but a few situations are different
Most people need both. Part A covers hospital stays; Part B covers doctor visits, outpatient care, and most preventive services. Without Part B you're exposed for the kind of care that's most common.
The exceptions are narrow but real. If you have active employer coverage at sixty-five and the rules above apply, you may defer Part B. If you're a TRICARE for Life beneficiary, you must enroll in Part B or you'll lose your TRICARE benefit — the rules are the opposite of optional. If you're a VA-only enrollee, deferring Part B is a known risk pattern; the VA covers VA care but not non-VA emergency or specialist care, and once you miss your IEP the late-enrollment penalty applies.
If you're not sure, the next card down is for you.
Need a side-by-side of what each Part covers? → See Part A and Part B explained
I'm past my IEP and I'm not enrolledThere's a path forward — but understand what you're walking into
If you missed your IEP and you don't qualify for a Special Enrollment Period, the General Enrollment Period is your path. It runs January first through March thirty-first each year. Coverage starts the month after you enroll.
The cost is the Part B late-enrollment penalty: ten percent added to your standard Part B premium for each twelve-month period you were eligible but not enrolled and didn't have other creditable coverage. It's a lifetime add, not a one-time fee — it rides with your premium for as long as you have Part B.
If you had creditable employer coverage during the gap, that may erase the penalty entirely under a Special Enrollment Period. Form CMS-L564 (Request for Employment Information) documents the coverage. Get this filled out by your former HR before you do anything else.
Want the full late-enrollment penalty walkthrough? → See Medicare late-enrollment penalty
I'm helping my parent enroll in MedicareTheir application, their identity, their signature — here's how to help without overstepping
A parent's Medicare enrollment has to be in their name. Their account, their identity verification, their signature on the application. You can sit with them, help them gather documents (birth certificate, proof of citizenship or lawful presence, Social Security number, employer coverage information if applicable), and call SHIP together at one-eight-seven-seven, eight-three-nine, two-six-seven-five for free counseling.
What you cannot do is sign for them. If your parent can no longer manage their own affairs, that's a separate, formal process called representative payee, and it's not something you set up at the enrollment counter. It involves SSA Form SSA-eleven and a determination by the agency that the beneficiary is incapable.
The most useful thing you can do as an adult child is be present — in person or on the phone — and take notes during calls with SSA, SHIP, and Medicare. The system assumes the beneficiary is the one engaging.
Filing for yourself? See the situation cards above. → Get help for someone else
I don't know which Parts I needThat's normal — here's where to get a real answer
If none of the situations above sounds like you, or if more than one does and you're not sure where to start, that's normal. Medicare's enrollment rules sit on top of three different statutory frameworks (Title XVIII of the Social Security Act, Title XIX cross-references, and the BENES Act simplifications) and most people only learn the system once.
Two phone numbers do most of the work. SHIP — the State Health Insurance Assistance Program — is free, unbiased counseling at one-eight-seven-seven, eight-three-nine, two-six-seven-five. They don't sell anything. SSA at one-eight-hundred, seven-seven-two, one-two-one-three handles the actual Part A and Part B enrollment.
The Chapter card on this page also offers free help from licensed Medicare advisors. They walk you through the comparison without an upfront fee.
Everything people ask me
When can I sign up for Medicare?
Most people sign up during the Initial Enrollment Period — the seven-month window that begins three months before your sixty-fifth birthday, includes your birthday month, and ends three months after. If you miss it and don't qualify for a Special Enrollment Period, the General Enrollment Period runs January first through March thirty-first each year. People with certain qualifying disabilities may enroll earlier.
What is the Initial Enrollment Period (IEP)?
The IEP is your seven-month enrollment window. It starts three months before the month you turn sixty-five, includes your birthday month, and ends three months after. During the IEP you can enroll in Part A, Part B, or both, without a late-enrollment penalty. Coverage starts the month after you enroll, under the BENES Act simplifications that took effect in 2023.
Do I get auto-enrolled in Medicare at 65?
Only if you're already receiving Social Security or Railroad Retirement Board benefits when you turn sixty-five. If you are, your Medicare card arrives in the mail roughly three months before your birthday and you're enrolled in both Part A and Part B automatically. If you haven't filed for Social Security, you have to actively apply for Medicare — most people do it at ssa.gov/medicare.
Where do I sign up for Medicare?
The Social Security Administration handles Medicare enrollment for Part A and Part B. Apply online at ssa.gov/medicare, by phone at 1-800-772-1213, or in person at a local SSA field office. If you'd rather have free unbiased help walking through the application, call SHIP at 1-877-839-2675. SHIP counselors don't sell anything — they explain the rules.
What's the difference between Part A and Part B?
Part A is hospital insurance — inpatient hospital stays, skilled nursing facility care, hospice, and some home health care. Most people qualify for premium-free Part A based on forty-plus quarters of Medicare-covered employment. Part B is medical insurance — doctor visits, outpatient care, durable medical equipment, and most preventive services. Part B has a monthly premium ($202.90 in 2026 for most enrollees, with higher amounts for higher incomes).
Do I need both Part A and Part B?
Most people need both. Part A by itself leaves you exposed for the kind of care that's most common — doctor visits, outpatient procedures, lab work. The narrow exceptions: active employer coverage at sixty-five (the working-aged SEP path), TRICARE for Life beneficiaries (who must enroll in Part B), and VA-only enrollees (who face Part B coverage gaps for non-VA care). If any of these sound like you, talk to SHIP at 1-877-839-2675 before you decide.
What happens if I don't sign up at 65?
If you didn't have other creditable coverage during the gap, you may face the Part B late-enrollment penalty: 10% added to your standard Part B premium for each 12-month period you were eligible but not enrolled. It's a lifetime add, not a one-time fee — it stays with your premium for as long as you have Part B. You'd then enroll during the General Enrollment Period (January 1 – March 31). If you had creditable employer coverage during the gap, a Special Enrollment Period may erase the penalty entirely.
When does my Medicare coverage start after I enroll?
Under the BENES Act (Consolidated Appropriations Act 2021), Medicare coverage starts the month after enrollment for most enrollees, regardless of which month inside your IEP you applied in. The pre-BENES rules — which delayed coverage for several months in some cases — no longer apply. If you enrolled during the General Enrollment Period (January – March), coverage also starts the month after enrollment.
Can I sign up for Medicare if I'm still working with employer coverage?
Yes — and the rules turn on employer size. If your employer has 20 or more employees, your group plan is generally primary at sixty-five and you may defer Part B without penalty using the working-aged Special Enrollment Period. Once your employment or group coverage ends, you have an 8-month SEP to enroll. If the employer has fewer than 20 employees, Medicare typically becomes primary at sixty-five — enrolling in Part B during your IEP is usually the right call. Get the employer's coverage details in writing and verify with SHIP before you decide.
Do I have to enroll in Medicare Advantage or Part D when I sign up for Original Medicare?
No. When you sign up for Part A and Part B you have Original Medicare. Medicare Advantage and Part D drug coverage are separate, optional decisions you can make later — typically during your IEP, the Annual Enrollment Period (October 15 – December 7), or a Special Enrollment Period if you qualify. If you're not sure which path is right for you, SHIP and licensed Medicare advisors can walk you through your specific situation.
Where to go next
Enrolling is the start, not the end. The pages below cover the concept-level stuff this walkthrough deliberately doesn't — what each Part actually covers, what happens if you keep working, what the late-enrollment penalty really costs.
Medicare enrollment periods explained
The companion concept page. Initial Enrollment Period, General Enrollment Period, Special Enrollment Periods, Annual Enrollment Period, Open Enrollment Period — all five explained side by side, with the dates and the rules. If this walkthrough was the action and you want the framework, that's the next page.
Working past 65 with employer coverage
If you have employer health insurance at sixty-five, the deferral path is critical and the rules turn on employer size. Twenty-plus employees and your group plan is generally primary; under twenty and Medicare usually becomes primary. Get this wrong and you may pay a late-enrollment penalty for life.
Medicare late-enrollment penalty
The Part B late-enrollment penalty is ten percent added to your premium for every twelve months you were eligible but not enrolled — lifetime, not temporary. The Part D late-enrollment penalty has its own math. This page covers what each one costs and how the SEP carve-outs work to erase it.
Medicare Part A explained
Hospital insurance — inpatient stays, skilled nursing facility care, hospice, and some home health. Most people qualify for premium-free Part A based on forty-plus quarters of Medicare-covered employment. The 2026 inpatient deductible and per-day coinsurance are covered on the dedicated Part A page.
Medicare Part B explained
Medical insurance — doctor visits, outpatient care, durable medical equipment, most preventive services. The 2026 standard premium and the income-related Monthly Adjustment Amount (IRMAA) tiers are covered on the dedicated Part B page. Most people enroll in Part B during their IEP.
Original Medicare vs Medicare Advantage
The biggest decision after enrollment. Original Medicare and Medicare Advantage are different roads with different tradeoffs — cost-sharing structure, network rules, supplement compatibility, prescription coverage. This page lays out the comparison without recommending plans.
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