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A guide to Medicare eligibility

In most cases, you're eligible at age 65 for comprehensive Medicare coverage

Louise Norris

In this article

For the vast majority of Americans who look forward to receiving Medicare health benefits, eligibility is as uncomplicated as celebrating your 65th birthday.

But your eligibility to receive Medicare coverage without having to pay a premium – and your eligibility for other Medicare plans – depends on such factors as your work history and your health status. Here’s what you need to know:

Am I eligible for Medicare Part A?

Generally, you’re eligible for Medicare Part A if you’re 65 years old and have been a legal resident of the U.S. for at least five years. In fact, the government will automatically enroll you in Medicare Part A at no cost when you reach 65 as long as you’re already collecting Social Security or Railroad Retirement Board benefits.

If you’re already receiving Social Security or Railroad Retirement benefits, all you need to do is check your mail for your Medicare card, which should automatically arrive in the mail about three months prior to your 65th birthday (or the 25th month of a disability, if you’re becoming eligible for Medicare due to disability rather than age). The card will arrive with the option to opt-out of Part B (see below), but opting out of Part B is only a good idea if you’re still working and have employer-sponsored coverage that provides the same or better coverage, or if your spouse is still working and you have coverage under their plan. (See our article that explains what you need to know about delaying Part B enrollment.)

If you’re not already receiving Social Security or Railroad Retirement benefits, you’ll need to enroll in Medicare during a seven-month open enrollment window that includes the three months before the month you turn 65, the month you turn 65, and the three following months. If you enroll before the month you turn 65, your benefits will start the month you turn 65 (or the month before, if your birthday is on the first of the month). If you enroll in the three months after you turn 65, your coverage could have a delayed effective date.

In addition to turning 65, people can become eligible for Medicare due to a disability (eligibility for Medicare starts after you’ve been receiving Social Security or Railroad Retirement Board disability benefits for two years), or due to end-stage renal disease (ESRD) or amyotrophic lateral sclerosis (ALS).

People with ESRD become eligible for Medicare on the fourth month of dialysis treatment, or earlier if they take part in home-dialysis training. People with ALS become eligible for Medicare the same month their disability benefits begin (and there’s no longer a five-month waiting period for disability benefits to begin after a person is diagnosed with ALS).

Most people don’t have to pay a premium for Medicare Part A. You’re eligible to receive Part A coverage premium-free if:

  • You are 65 and you or your current or former spouse has paid Medicare taxes for at least 10 years.
  • You’re not yet 65, but you’re disabled and you or your spouse has paid Medicare taxes for at least 10 years. After you’ve received Social Security disability benefits or Railroad Retirement Board disability benefits for two years, you’ll be eligible for Medicare, with no premiums for Part A (the two-year waiting period does not apply for people with ESRD or ALS). In the case of a disabled child, eligibility for Medicare is based on a parent’s work history, and this can continue after the child reaches adulthood.

If you (or your spouse) have not been paying Medicare (FICA) taxes for at least 10 years, you’ll still be eligible to buy Part A coverage, but you’ll need to pay a premium, which varies based on your work history. Your premium in 2022 will be $499 a month if you’ve paid into Medicare (FICA taxes) less than 7.5 years, and $274 a month if you’ve paid Medicare taxes for at least 7.5 years but less than 10 years.

Am I eligible for Medicare Part B?

When you receive notification that you’re eligible for Medicare Part A, you’ll also be notified that you’re eligible for Part B coverage, which is optional and has a premium for all enrollees.

Part B costs $170.10/month for most enrollees in 2022, although Part B costs more if your income is more than $91,000 (or $182,000 for a married couple; note that these amounts were indexed for inflation starting in 2020; and the determination for 2022 is based on your tax return from 2020).

It’s important to enroll in both Part A and Part B. You have an enrollment window that runs for seven months (in most cases, beginning three months prior to the month you turn 65 and continuing for three months afterward). And while you can enroll in the three months following your 65th birthday, it’s best to enroll in Part B early, or you could have gaps in health coverage. If you wait too long, you could end up locked out of Part B and have to wait until the next general Medicare enrollment period.

If you don’t enroll during your initial window, you won’t lose eligibility for Part B, but you will be penalized with an increased premium when you eventually enroll, which climbs 10% for each year that you’re eligible but don’t enroll in Part B (note that there’s no penalty if you delay Part B because you’re covered by a current employer’s plan, either your own or your spouse’s). The General Enrollment Period (GEP) for Medicare A and B runs from January 1 to March 31 each year, for coverage effective July 1 — with an increased premium if the late enrollment penalty applies.

How do I become eligible for Medicare Advantage?

If you’re eligible for Medicare benefits, you have to choose how to receive them – either through the government-run Original Medicare program, or through Medicare Advantage. The majority of all Medicare beneficiaries use Original Medicare, but more than four in ten are enrolled in Medicare Advantage plans, and Advantage enrollment has been steadily climbing at a much faster pace than overall Medicare enrollment.

You need to have (or be eligible for) both Medicare Part A and Part B in order to enroll in Medicare Advantage, and you can select a plan during your Medicare initial enrollment period — the seven months surrounding the month you qualify for Medicare (note that there are some rural areas of the country where Medicare Advantage plans are not available; you have to live in an area where Advantage plans are offered in order to enroll in one).

Most Medicare Advantage plans also include Part D prescription drug coverage; if you have a Medicare Advantage plan, you typically receive your Part D coverage together with the health and hospital benefits, in one single package, although the maximum out-of-pocket limits for Medicare Advantage (no more than $7,550) do not include the cost of prescription drugs.

People with end-stage renal disease (ESRD) are eligible for Medicare, but used to be ineligible for most Medicare Advantage plans. This changed as of 2021, however, under the terms of the 21st Century Cures Act. As of 2021, people with ESRD have the same access to Medicare Advantage plans as other Medicare beneficiaries.

When can I enroll in Medicare Part D?

To be eligible for Medicare Part D prescription drug coverage, you must have either Medicare Part A or Part B, or both. You can sign up for Medicare Part D at the same time that you enroll in Medicare Part A and B.

As mentioned above, most people who select Medicare Advantage must receive their Part D prescription benefits as part of that same Medicare Advantage plan (89% of all Medicare Advantage plans include Part D coverage in 2022). Medicare Savings Account (MSA) plans do not include Part D coverage, nor do some Private Fee-for-Service (PFFS) Medicare plans. If you have an MSA or a PFFS and it doesn’t have Part D coverage included, you’re allowed to purchase a stand-alone Part D plan to supplement it.

As with Part B, you are still eligible for Part D prescription drug coverage if you don’t enroll when you’re first eligible, but you may pay higher premiums if you enroll later on, unless you had creditable coverage from another plan during the time that you delayed enrollment in Part D.

Who's eligible for Medigap?

If you’re enrolled in both Medicare Part A and Part B, and don’t have Medicare Advantage or Medicaid benefits, then you’re eligible to apply for a Medigap policy. These plans are standardized, and are designed to cover some or all of the out-of-pocket costs that are incurred when you have a Medicare-covered claim (ie, they pay some or all of your deductible and coinsurance).

You have a federal right to buy a Medigap plan during the six months beginning when you’re at least 65 years old and have enrolled in Part B. This is known as your Medigap open enrollment period. After this time runs out, you will have only limited chances to purchase one down the road.

Some states allow people of any age or health status to purchase Medigap coverage at any time (or during a specific window each year) without medical underwriting, but most don’t. In many states, Medigap plans may not be available for people who have Medicare before age 65. There are 33 states that require Medigap plans to be guaranteed issue in at least some circumstances when an applicant is under age 65, but the rules vary from one state to another; you can click on a state on this map to see details about state-based Medigap rules.

If you’re enrolling in Medicare due to your age, the primary factor that will affect your ability to purchase a Medigap policy – regardless of your health – will be whether you enroll during your Medigap Open Enrollment Period.

If you don’t enroll during your Medigap open enrollment period, carriers in most states are allowed to use your medical history to determine eligibility for coverage and to set your premium if you apply for coverage later on. Read more about Medigap plan eligibility and enrollment.

Louise Norris is an individual health insurance broker who has been writing about health insurance and health reform since 2006. She has written dozens of opinions and educational pieces about the Affordable Care Act for Her state health exchange updates and open enrollment guide are regularly cited by media who cover health reform and by other health insurance experts.

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