How to Enroll in Medicare: A Step-by-Step Guide
July 5, 2026
How to Enroll in Medicare in 2026
Enrolling in Medicare starts with knowing when your window opens, which parts of Medicare you need, and how to apply. For most people turning 65, enrollment happens through the Social Security Administration (SSA), either automatically or with a short online application. If you miss your initial window, late enrollment penalties can follow you for years, so getting the timing right matters.
Medicare is the federal health insurance program run by the Centers for Medicare & Medicaid Services (CMS). It covers adults 65 and older, as well as younger people with certain disabilities, End-Stage Renal Disease (ESRD), or Amyotrophic Lateral Sclerosis (ALS). The program is divided into four parts: Part A (hospital insurance), Part B (medical insurance), Part C (Medicare Advantage, offered by private insurers), and Part D (prescription drug coverage).
This guide walks you through every stage of enrollment, from your Initial Enrollment Period through choosing additional coverage, so you can make a confident decision on your own schedule. If you are turning 65 and exploring Medicare for the first time, start here.
Medicare Enrollment by the Numbers
Who Is Eligible to Enroll in Medicare?
Most people become eligible for Medicare at age 65. You qualify for premium-free Part A if you or your spouse worked and paid Medicare taxes for at least 10 years (40 quarters). If you do not meet that work history requirement, you can still enroll in Part A by paying a monthly premium.
People under 65 may also qualify for Medicare in specific situations:
- Disability: If you have received Social Security Disability Insurance (SSDI) benefits for 24 consecutive months, you are automatically enrolled in Medicare Parts A and B.
- ALS (Lou Gehrig's Disease): You are enrolled in Medicare immediately upon receiving SSDI, no waiting period.
- End-Stage Renal Disease (ESRD): You can apply for Medicare at any age if you have permanent kidney failure requiring dialysis or a transplant.
For a full breakdown of non-age-based eligibility, see our guide on Medicare under 65.
How to Enroll in Medicare: Step by Step
Find out if you will be enrolled automatically
If you are already receiving Social Security retirement or Railroad Retirement Board (RRB) benefits when you turn 65, you will be enrolled in Medicare Parts A and B automatically. Your red, white, and blue Medicare card will arrive in the mail about three months before your 65th birthday.
Apply during your Initial Enrollment Period if you are not automatic
If you are not yet drawing Social Security, you must actively sign up. Your Initial Enrollment Period (IEP) lasts seven months: the three months before your birthday month, your birthday month itself, and the three months after. Applying early, before your birthday month, means your coverage starts the first day of your birthday month.
Apply online, by phone, or in person
The fastest method is the online application at SSA.gov, which takes about 10 minutes. You can also call the SSA at 1-800-772-1213 or visit your local Social Security office. You do not need to go in person unless you prefer it.
Decide whether to keep Part B or defer it
If you are still working and covered by an employer group health plan with 20 or more employees, you may be able to delay Part B without penalty. If your employer plan covers fewer than 20 employees, Medicare becomes your primary insurance and you should enroll in Part B to avoid a coverage gap.
Choose additional coverage: Part C or Part D
Original Medicare (Parts A and B) does not cover prescriptions or cap your out-of-pocket costs. After enrolling, you have the option to add a Part D drug plan, a Medicare Supplement (Medigap) policy, or a Medicare Advantage (Part C) plan that bundles all coverage together. Review your options during your initial enrollment window for the widest choice.
Understanding Your Medicare Enrollment Windows
Initial Enrollment Period (IEP)
Your IEP is your first and most important enrollment window. It is tied to your 65th birthday and lasts exactly seven months. Medicare.gov confirms that when you enroll affects when coverage begins:
- Months 1-3 (before your birthday month): Coverage starts the first day of your birthday month.
- Month 4 (your birthday month): Coverage starts the first day of the following month.
- Months 5-7 (after your birthday month): Coverage starts one to two months after you enroll.
Enrolling in the three months before your birthday month gives you the earliest possible start date with no gap in coverage.
Special Enrollment Period (SEP)
If you or your spouse are still working past 65 and covered by an employer or union group health plan, you qualify for a Special Enrollment Period. The SEP allows you to enroll in Part B without penalty any time while you have employer coverage, plus eight months after that coverage ends. This is different from COBRA or retiree coverage, those do not trigger an SEP. Review your situation with your employer's benefits office before delaying Part B.
Understanding these windows is essential for knowing what to do about Medicare when you retire later than 65.
General Enrollment Period (GEP)
If you miss your IEP and do not qualify for an SEP, you can enroll during the General Enrollment Period, which runs January 1 through March 31 each year. Coverage under the GEP begins July 1. Missing your IEP and relying on the GEP means a gap in coverage and likely a permanent Medicare late enrollment penalty on your Part B premium.
Enrollment Timing: What Changes Based on When You Apply
| Feature | Enrollment Window | RecommendedCoverage Start | Penalty Risk |
|---|---|---|---|
| Already receiving Social Security at 65 | Automatic | First day of birthday month | None |
| Not on Social Security, apply months 1-3 of IEP | Initial Enrollment Period | First day of birthday month | None |
| Apply during birthday month or months 5-7 of IEP | Initial Enrollment Period | 1-2 months after enrollment | None |
| Still working with employer coverage past 65 | Special Enrollment Period | Flexible, up to 8 months after employer coverage ends | None if enrolled timely |
| Missed IEP, no qualifying SEP | General Enrollment Period (Jan-Mar) | July 1 | Permanent Part B penalty likely |
What Happens After You Enroll in Parts A and B?
Once you have Original Medicare, you have three main directions for adding coverage:
Option 1: Add a Part D Drug Plan
Part D covers prescription medications. You purchase a standalone Part D plan from a private insurer. Plans vary in cost, covered drugs (formulary), and pharmacy networks, so comparing options is important. If you do not sign up for Part D when you are first eligible and you go without creditable drug coverage for 63 or more consecutive days, you may face a permanent Part D late enrollment penalty. Learn more about Part D prescription coverage.
Option 2: Add a Medicare Supplement (Medigap) Policy
Medigap plans, sold by private insurers, help pay the out-of-pocket costs that Original Medicare does not cover, such as deductibles, coinsurance, and copayments. Your open enrollment window for Medigap starts the month you are both 65 and enrolled in Part B and lasts six months. During this window, insurers cannot deny you coverage or charge you more based on health conditions. Outside this window, medical underwriting may apply. Our guide to Medicare Supplement plans covers what each plan letter includes.
Option 3: Switch to Medicare Advantage (Part C)
Medicare Advantage plans are offered by private insurers approved by CMS. They bundle Part A, Part B, and usually Part D into a single plan, and often include extra benefits like dental, vision, and hearing coverage. You must remain enrolled in both Part A and Part B to join a Medicare Advantage plan. If you choose Medicare Advantage, you generally cannot use a Medigap policy alongside it.
You can switch between Medicare Advantage and Original Medicare during the Medicare annual enrollment period, which runs October 15 through December 7 each year. Changes take effect January 1.
Do not delay Part B unless you have qualifying employer coverage
The Part B late enrollment penalty is permanent. For each 12-month period you were eligible but did not enroll, your monthly Part B premium increases by 10%, and that increase stays with you as long as you have Medicare. COBRA and retiree health coverage do not count as qualifying coverage for avoiding the penalty. Only active employer or union group health plan coverage based on your own or your spouse's current employment qualifies. If you are unsure, contact the Social Security Administration before declining Part B.
Key Things to Know Before You Enroll
Apply up to 3 months early
Enrolling in the three months before your birthday month gives you the earliest coverage start date and the most time to compare drug and supplement plans.
Premium-free Part A for most
If you worked and paid Medicare taxes for at least 10 years, you pay no monthly premium for Part A. Part B has a standard monthly premium, $185.00 in 2026 for most enrollees.
Keep your Medicare card safe
Your Medicare card shows your Medicare number (not your Social Security number). If your card is lost or stolen, you can request a replacement through your Medicare.gov account or by calling 1-800-MEDICARE.
Low-income help is available
Medicare Savings Programs can help pay Part A and B premiums, deductibles, and copayments for people with limited income and resources. Four programs exist: QMB, SLMB, QI, and QDWI.
Spouses have separate enrollment
Each spouse enrolls individually. Your spouse's work history can qualify you for premium-free Part A even if you did not work enough quarters yourself.
Review plan options annually
Even after initial enrollment, compare Part D and Medicare Advantage plans each fall during the Annual Enrollment Period. Plans change their costs and formularies yearly.
Medicare Savings Programs: Help With Costs
If your income and resources are limited, you may qualify for one of four Medicare Savings Programs administered by your state Medicaid office. According to Medicare.gov, these programs can pay some or all of your Medicare premiums, deductibles, coinsurance, and copayments:
- Qualified Medicare Beneficiary (QMB): Covers Part A and Part B premiums, deductibles, coinsurance, and copayments.
- Specified Low-Income Medicare Beneficiary (SLMB): Covers Part B premiums only.
- Qualifying Individual (QI): Covers Part B premiums only; funding is limited and applications are processed first-come, first-served each year.
- Qualified Disabled Working Individual (QDWI): Covers Part A premiums for certain working people with disabilities under 65.
Income and asset limits for these programs are set by each state and updated annually. Contact your state Medicaid office or call 1-800-MEDICARE to find out if you qualify and how to apply.
Get free Medicare enrollment guidance
Not sure which parts to enroll in or when your window opens? Get plain-language help matched to your situation, no pressure, no obligation.
Frequently Asked Questions About Enrolling in Medicare
Your Initial Enrollment Period opens three months before your 65th birthday month. Enrolling during those first three months gives you coverage starting on the first day of your birthday month, with no gap. If you wait until your birthday month or later, your start date shifts by one or two months. Apply early to keep your coverage continuous.
Not necessarily. If you are covered by an employer or union group health plan through your own or your spouse's active employment, and the employer has 20 or more employees, you can delay Part B without penalty. You will have a Special Enrollment Period to sign up after that coverage ends. If your employer has fewer than 20 employees, Medicare becomes your primary payer and you should enroll in Part B to avoid coverage gaps and penalties. COBRA and retiree coverage do not count as employer coverage for this purpose.
You can apply for Medicare Parts A and B at SSA.gov. The online application takes about 10 minutes and does not require a trip to a Social Security office. You will need your Social Security number, birth certificate information, and employment details. You can also call 1-800-772-1213 or visit a local Social Security office if you prefer to apply in person.
The Part B late enrollment penalty adds 10% to your monthly Part B premium for each full 12-month period you were eligible but did not enroll without a qualifying reason. This penalty is permanent, it stays with you as long as you have Part B. The Part D late enrollment penalty is calculated differently: 1% of the national base beneficiary premium for each month without creditable drug coverage. Both penalties are avoidable if you enroll on time or qualify for a Special Enrollment Period. Read our full guide to the Medicare late enrollment penalty for detailed examples.
Part A covers inpatient hospital stays, skilled nursing facility care, hospice, and some home health services. Part B covers doctor visits, outpatient care, preventive services, and durable medical equipment. Together, Parts A and B make up Original Medicare. Part C (Medicare Advantage) is an alternative way to get your Medicare benefits through a private insurer that bundles Parts A and B, and usually Part D. Part D is standalone prescription drug coverage added to Original Medicare.
You are automatically enrolled in Medicare Parts A and B if you are already receiving Social Security retirement benefits or Railroad Retirement Board benefits when you turn 65. Your Medicare card will arrive about three months before your birthday. If you are under 65 and receiving Social Security Disability Insurance (SSDI), you are automatically enrolled after 24 months of benefits, or immediately if you have ALS. If you are not receiving Social Security benefits when you turn 65, you must actively sign up.
Yes. You can still enroll in Part B at 65 regardless of your work history. For Part A, if you did not work enough quarters to qualify for premium-free coverage, you can buy into Part A by paying a monthly premium, up to $505 per month in 2026 if you have fewer than 30 quarters of Medicare-covered work. Enrolling through a spouse's work record is also an option if your spouse worked at least 40 quarters.
Original Medicare (Parts A and B) works nationwide, you can see any doctor or hospital that accepts Medicare, regardless of where you live. If you are enrolled in a Medicare Advantage plan or Part D plan, those are regional and you may need to switch plans when you move. Most plans have a Special Enrollment Period triggered by a permanent move out of the plan's service area.
After your Initial Enrollment Period, the main window for changing coverage is the Annual Enrollment Period (AEP), which runs October 15 through December 7 each year. During the AEP, you can switch between Original Medicare and Medicare Advantage, change your Part D plan, or add Part D if you did not enroll earlier. Changes made during AEP take effect January 1. Learn more about the Medicare annual enrollment period and what you can change.
Original Medicare (Parts A and B) generally does not cover routine dental care, eyeglasses, or hearing aids. Some Medicare Advantage (Part C) plans include these benefits as extras beyond what Original Medicare offers. If these services matter to you, compare Medicare Advantage plans in your area to see which extras are included and at what cost.