Who Medicare Covers and When You Become Eligible

Medicare is for people 65 and older, regardless of income or health history

Yes, Medicare is the federal health insurance program for people age 65 and older. You do not need to be retired, poor, or sick to join — age 65 is the main threshold. The program also covers some younger people with disabilities, people with end-stage renal disease, and people with ALS (amyotrophic lateral sclerosis), but the vast majority of Medicare members are seniors.

Medicare is run by the Centers for Medicare & Medicaid Services (CMS), a division of the U.S. Department of Health and Human Services. It is funded through payroll taxes during your working years and through premiums you pay once you enroll. Unlike Medicaid, which is means-tested and varies by state, Medicare is the same program nationwide for anyone who meets the age or disability requirement.

Key Takeaways

You become may be able to access for Medicare at age 65, and you should enroll during your initial enrollment period to avoid paying higher premiums later.
Medicare has four parts — Part A (hospital), Part B (doctor visits), Part D (prescription drugs), and Part C (an alternative that bundles coverage) — and you choose which parts you need.
You can enroll online at Medicare.gov, by phone at 1-800-MEDICARE, or in person at your local Social Security office.
If you delay enrolling past age 65 without a valid reason, you will pay a permanent penalty on your premiums for as long as you have Medicare.

When you turn 65 and how to enroll

Your initial enrollment period begins three months before the month you turn 65 and ends three months after. During this seven-month window, you can enroll in Medicare without penalty. For example, if you turn 65 in June, you can enroll starting in March and through September.

You do not have to wait until your birthday month to sign up. Many people enroll as soon as the window opens, which gives them time to choose their coverage and ask questions. You can enroll online at Medicare.gov, call 1-800-MEDICARE (1-800-633-4227), or visit your local Social Security office in person.

If you miss your initial enrollment period and do not have a valid reason (such as still being covered by an employer plan), you will pay a late enrollment penalty on your premiums. This penalty is permanent — you keep paying it for as long as you have Medicare, even if you enroll years later. The penalty amount increases the longer you wait, so enrolling on time matters financially.

What Medicare covers and what it does not

Medicare Part A covers hospital stays, skilled nursing facility care, hospice, and some home health services. Part B covers doctor visits, outpatient care, lab tests, and preventive services. Part D covers prescription drugs. Together, these are called Original Medicare.

Medicare does not cover dental, vision, hearing aids, or long-term custodial care (like assisted living or nursing home care for non-medical reasons). It also does not cover routine foot care, cosmetic surgery, or most over-the-counter medications. You can buy a Medigap policy (supplemental insurance) to fill some of these gaps, or you can choose Part C (Medicare Advantage), which is an alternative plan run by private insurers that often includes dental and vision but has different rules about which doctors you can see.

How much Medicare costs

Part A has no monthly premium for most people because they paid Medicare taxes while working. Part B has a monthly premium that changes each year; in 2024 it ranges from $174.70 to $610.50 depending on your income. Part D premiums vary by plan and range widely. Part C (Medicare Advantage) plans often have no monthly premium but charge copays when you use services.

You also pay deductibles and copays when you use services. Part A has a deductible per hospital stay. Part B has an annual deductible, then you pay 20 percent of the cost of most services. Part D has a deductible and then tiered copays for different drugs. These costs change yearly, so check Medicare.gov each fall during open enrollment to see what your costs will be.

If your income is low, you may be able to get help paying premiums and cost-sharing through programs like the Low-Income Subsidy (LIS) or Medicaid. Your state Medicaid office or a local Area Agency on Aging can tell you whether you may have access to.

Medicare Advantage versus Original Medicare

Original Medicare (Part A and Part B) lets you see any doctor or hospital that accepts Medicare. You pay the costs Medicare does not cover out of pocket, unless you buy a Medigap policy. Medigap policies are sold by private insurers and help pay deductibles, copays, and coinsurance.

Medicare Advantage (Part C) is an alternative. You enroll in a plan run by a private insurance company instead of using Original Medicare. Most Advantage plans have lower or no monthly premiums, but they usually require you to use doctors and hospitals in their network. They often include dental, vision, and hearing coverage that Original Medicare does not. However, they may have higher copays and stricter rules about which specialists you can see without a referral.

You can switch between Original Medicare and Medicare Advantage during the annual open enrollment period, which runs from October 15 to December 7 each year. Changes take effect January 1. If you are happy with your current plan, you do not have to do anything — your coverage continues automatically.

Special situations: working past 65 or having employer coverage

If you are still working and covered by your employer's health plan at age 65, you may be able to delay enrolling in Medicare without penalty. This is called creditable coverage. You will need to show that your employer plan is at least as good as Medicare. Ask your employer's benefits office whether your plan qualifies.

If you delay based on employer coverage and then lose that coverage, you have a special enrollment period to sign up for Medicare without penalty. The window is usually eight months from the date you lose coverage or turn 65, whichever is later. Keep documentation of when your employer coverage ended so you can prove you had a valid reason to delay.

If you are a federal employee, railroad retiree, or military retiree, you may have different rules. Contact your agency's benefits office to learn how your coverage interacts with Medicare.

How to prepare before you turn 65

Start by creating a Medicare.gov account at least a month before your enrollment period begins. You will need your Social Security number and email address. Your account lets you view your enrollment status, see your claims, and compare plans.

Gather a list of your current doctors and medications. When you compare plans, you can check whether your doctors are in-network and whether your drugs are covered. If your current doctor is not in a plan's network, you may want to choose a different plan or ask your doctor which plans they accept.

If you need help understanding your options, contact your local State Health Insurance information Program (SHIP). SHIP counselors are free and unbiased. You can find your state's SHIP by calling 1-800-MEDICARE or visiting Medicare.gov. You can also call the Eldercare Locator at 1-800-677-1116 to find local resources.

Frequently Asked Questions

Do I have to enroll in Medicare at 65 if I am still working?

Not if you have employer coverage. If your employer has 20 or more employees, your employer plan is primary and Medicare is secondary. You can delay Medicare without penalty as long as you are covered by the employer plan. Once you leave that job, you have eight months to enroll without penalty.

What happens if I miss my enrollment important date?

You can still enroll, but you will pay a permanent late enrollment penalty on your premiums. The penalty is 10 percent of the Part B premium for each full year you were may be able to access but not enrolled. This penalty stays with you for life, so it is worth enrolling as soon as you can even if you are late.

Can I change my Medicare plan after I enroll?

Yes, during the annual open enrollment period from October 15 to December 7. You can switch between Original Medicare and Medicare Advantage, or change to a different plan within either category. Changes take effect January 1. Outside this window, you can only change plans if you have a may have access to life event, such as moving, losing coverage, or getting married.

Does Medicare cover preventive care?

Yes. Medicare Part B covers many preventive services at no cost to you, including annual wellness visits, cancer screenings, cardiovascular screenings, and vaccinations. You pay nothing if your doctor accepts Medicare assignment. Check Medicare.gov for the full list of covered preventive services.

What if I cannot afford Medicare premiums?

If your income is low, you may may have access to for the Low-Income Subsidy program, which helps pay Part D premiums and cost-sharing. You may also may have access to for Medicaid, which can pay your Medicare premiums and cover services Medicare does not. Contact your state Medicaid office or call 1-800-MEDICARE to learn about programs in your area.

This guide is for general information only and is not medical, financial, legal, or other professional advice. For decisions specific to your situation, consult a qualified professional. See our Editorial Policy.