The Basic Rule: Age 65 and Older

You become covered by Medicare automatically when you turn 65, as long as you or your spouse paid Medicare taxes while working. You do not have to do anything on your birthday — the Social Security Administration enrolls you in Medicare Part A (hospital insurance) and Part B (medical insurance) three months before the month you turn 65. If you were born on the first of the month, your coverage starts the previous month.

This automatic enrollment happens whether you are still working or retired. If you are still employed and earning income, you stay covered. If you have not yet claimed Social Security benefits, Medicare enrollment is separate — you get Medicare at 65 even if you wait until 70 to claim retirement benefits.

The requirement that you or your spouse paid Medicare taxes means you need at least 40 quarters of coverage (roughly 10 years of work). If you do not have 40 quarters yourself, you may be covered under your spouse's work record if you have been married at least two years.

Key Takeaways

  • You are automatically enrolled in Medicare at age 65 if you or your spouse paid Medicare taxes for at least 40 quarters during your working years.
  • People under 65 with end-stage renal disease, ALS, or permanent disability after 24 months on Social Security Disability Insurance can receive Medicare before retirement age.
  • You must actively choose whether to enroll in Part D (prescription drug coverage) during your initial enrollment window, or face a permanent penalty if you go without coverage.
  • If you delay enrolling in Part B after turning 65 while still working, you must enroll within eight months of leaving your job to avoid late penalties.
  • Non-citizens must have been a permanent resident for at least five years and live in the United States to be covered by Medicare.

Medicare Before Age 65: Disability and Kidney Disease

You can receive Medicare before 65 if you have been receiving Social Security Disability Insurance (SSDI) for 24 months. The 24 months starts from the month you were approved for disability, not from when you applied. Once you have been on SSDI for two years, Medicare Part A and Part B coverage begins automatically.

You also may have access to for Medicare at any age if you have end-stage renal disease (ESRD) — permanent kidney failure requiring dialysis or a transplant. Coverage begins the first day of the month in which your dialysis treatment starts, or the month you have a kidney transplant, whichever comes first. If you are already on dialysis when you explore, coverage can be backdated to the month treatment began.

A third group is people with amyotrophic lateral sclerosis (ALS, also called Lou Gehrig's disease). You become covered by Medicare the first day of the month you are approved for SSDI, with no 24-month waiting period. This is the only condition that waives the two-year requirement.

Citizenship and Residency Requirements

You must be a U.S. citizen or a permanent resident (green card holder) to receive Medicare. If you are a permanent resident, you must have held that status for at least five consecutive years. The five years do not have to be when ready before you turn 65 — they can be any five years since you became a permanent resident.

You also must be a resident of the United States. This means you live in one of the 50 states, Washington D.C., or one of the U.S. territories (Puerto Rico, the U.S. Virgin Islands, Guam, American Samoa, or the Northern Mariana Islands). If you move outside the United States, your Medicare coverage continues, but some benefits may not be available to you in other countries.

What Happens If You Do Not Meet the Work Requirement

If you reach 65 but do not have 40 quarters of Medicare tax coverage, you can still purchase Part A coverage. The monthly premium varies based on how many quarters you have. If you have 30 to 39 quarters, the premium is lower than if you have fewer than 30 quarters. You can also buy Part B coverage on its own.

Buying Part A and Part B as an uninsured person is more expensive than the standard enrollment, and you will pay this higher premium for as long as you have Medicare. There is no way to lower it later by working more quarters. This is why it matters to check your work record with Social Security before you turn 65 — if you are close to 40 quarters, you may be able to work a bit longer and avoid the higher premium.

Enrollment Timing and Penalties for Delays

Your initial enrollment window is seven months long: three months before the month you turn 65, the month you turn 65, and three months after. If you enroll during this window, your coverage starts on the first day of the month you turn 65 (or the month after, depending on when you enroll).

If you miss this window, you can still enroll later, but you will pay a permanent penalty on your Part B premium. The penalty is 10 percent of the standard Part B premium for each full year you were may be able to access but not enrolled. This penalty stays with you for life.

There is one exception: if you are still working and covered by your employer's health plan when you turn 65, you can delay enrolling in Part B without penalty. You have eight months after you leave your job to enroll. You must enroll within this window, or the late penalty applies.

Part D Enrollment and the Prescription Drug Penalty

Part D (prescription drug coverage) works differently from Part A and Part B. You are not automatically enrolled in Part D. You must actively choose a plan during your initial enrollment window, or you will not have prescription drug coverage.

If you go without Part D coverage and later enroll, you will pay a permanent penalty on your Part D premium. The penalty is 1 percent of the national average Part D premium for each month you were may be able to access but not enrolled. Like the Part B penalty, this stays with you for life.

The exception is if you have other creditable prescription drug coverage — through an employer, a spouse's employer, or a state program — that is at least as good as Medicare Part D. If you have this coverage, you can delay enrolling in Part D without penalty. You must show proof of this coverage when you eventually enroll.

Special Cases: Government Employees and Railroad Workers

Some federal employees, state employees, and railroad workers have different Medicare rules. Federal employees hired before 1984 may not have paid Medicare taxes and may not be covered by Medicare at 65. Railroad workers have their own retirement system (the Railroad Retirement Board) that coordinates with Medicare.

If you are a current or former government employee or railroad worker, contact the Social Security Administration or your former employer's benefits office to confirm your coverage status before you turn 65. Do not assume you are covered — some of these groups have limited or no Medicare coverage.

Frequently Asked Questions

What if I was born outside the United States but became a citizen?

You are covered by Medicare at 65 if you are a U.S. citizen, regardless of where you were born. You do not need to have been a citizen for any minimum length of time. If you became a citizen after age 65, you may be able to enroll in Medicare retroactively — contact Social Security to ask about your specific situation.

Can my spouse get Medicare based on my work record?

Your spouse can receive Medicare at 62 (or earlier if they have a disability) based on your work record if you have at least 40 quarters of coverage. They do not need their own work history. Your spouse must be married to you for at least two years, or be the parent of your child, to use your record.

Do I lose Medicare if I move to another country?

Your Medicare Part A and Part B coverage continues even if you move abroad. However, most services outside the United States are not covered. You can use Medicare in Canada and Mexico for emergency care, and some other countries have reciprocal agreements, but routine care is usually not covered. Check with Medicare before you move.

What if I worked in multiple countries?

Only work in the United States counts toward the 40 quarters requirement for Medicare. Work in other countries does not count, even if you paid into that country's social security system. Some countries have agreements with the United States that allow work credits to be combined, but this is rare — ask Social Security if your situation may may have access to.

Can I get Medicare if I am still working past 65?

Yes. You are covered by Medicare at 65 whether you are working or retired. If you are still employed and your employer offers health coverage, you can keep that coverage and delay enrolling in Part B without penalty. You have eight months after you leave your job to enroll in Part B.