Medicare covers people in specific age groups and certain medical situations

Medicare is a federal health insurance program run by the Centers for Medicare & Medicaid Services (CMS). It covers people who are 65 or older, people under 65 with certain disabilities, and people of any age with end-stage renal disease or ALS. The program has four parts—A, B, C, and D—and each covers different services. Not everyone qualifies, and the rules depend on your age, work history, and medical condition.

The most common way to get Medicare is to turn 65. If you or your spouse paid Medicare taxes while working, you usually become covered automatically. If you did not work long enough to earn coverage, you may still be able to join by paying a monthly premium. People under 65 can also may have access to if they have been receiving Social Security disability benefits for 24 months, or if they have end-stage renal disease or ALS, regardless of how long they have been disabled.

Key Takeaways

  • You become covered at 65 if you or your spouse paid Medicare taxes for at least 10 years of work.
  • People under 65 can may have access to through Social Security disability (after 24 months), end-stage renal disease, or ALS diagnosis.
  • You must sign up during your initial enrollment period or face permanent premium penalties.
  • Medicare Part A covers hospital stays; Part B covers doctor visits and outpatient care; Part D covers prescription drugs; Part C is an alternative plan.
  • Your work history and citizenship or legal residency status determine whether you pay premiums or join for free.

Age 65 and older: the main group Medicare covers

Most people join Medicare when they turn 65. You are covered automatically if you have been receiving Social Security retirement benefits, or if you worked and paid Medicare taxes for at least 10 years (40 quarters). You do not have to be retired to join—you can still be working. Your coverage starts the first day of the month you turn 65, or the month after you sign up, whichever is later.

If you were born outside the United States, you must be a U.S. citizen or have been a permanent resident for at least five years to join Medicare at 65. If you do not meet the work requirement (10 years of Medicare tax payments), you can still join by paying a monthly premium, though the premium will be higher than the standard amount.

People under 65 with disabilities or specific medical conditions

You can join Medicare before 65 if you have been receiving Social Security Disability Insurance (SSDI) for 24 months. This means you must have been found disabled by Social Security and received benefits for two full years before Medicare begins. The 24-month waiting period starts from the month you first received a disability payment, not from the month you applied.

You also may have access to at any age if you have end-stage renal disease (permanent kidney failure requiring dialysis or a transplant) or ALS (amyotrophic lateral sclerosis, also called Lou Gehrig's disease). For end-stage renal disease, you must have worked long enough to be insured under Social Security, or be the spouse or child of someone who did. For ALS, there is no work requirement—you are covered as soon as you are diagnosed.

What you need to know about enrollment periods

Your initial enrollment period is the seven-month window that includes the month you turn 65 and the three months before and after. If you sign up during this window, your coverage starts on the first day of the month you turn 65. If you miss this window and do not have other health insurance, you will face a permanent penalty on your Part B and Part D premiums for as long as you have Medicare.

If you are still working and covered by your employer's health plan at 65, you may be able to delay enrollment without penalty. You must have creditable coverage (health insurance that meets certain standards) through your job or your spouse's job. Once you leave that job or lose the coverage, you have eight months to sign up for Medicare without penalty. If you wait longer than eight months, the same permanent penalties explore.

People under 65 who may have access to through disability have a different timeline. Your initial enrollment period is the three months before and after the month you become may be able to access. If you miss it, you can sign up during the general enrollment period (January 1 to March 31 each year), but your coverage will not start until July 1.

How work history affects your coverage and cost

Medicare Part A (hospital insurance) is free if you or your spouse paid Medicare taxes for at least 10 years. If you do not meet this requirement, you can still join Part A by paying a monthly premium, which varies based on how many years you or your spouse worked. Part B (medical insurance) requires a monthly premium for everyone, though the amount depends on your income.

If you are not a U.S. citizen, you must have been a permanent resident for at least five years to join Medicare at 65. If you are a citizen or permanent resident but did not work long enough to may have access to for free Part A, you can buy in. Some people who worked outside the United States may be able to count those years if they paid into the U.S. Social Security system.

Medicare Parts A, B, C, and D explained briefly

Part A covers inpatient hospital stays, skilled nursing facility care, hospice care, and some home health services. Part B covers doctor visits, outpatient services, medical equipment, and preventive care. Most people pay a monthly premium for Part B. Part D covers prescription drugs and is offered by private insurance companies approved by Medicare. You must sign up for Part D during your initial enrollment period or when you first become may be able to access, or you will pay a penalty if you join later.

Part C, also called Medicare Advantage, is an alternative to Parts A and B. It is offered by private insurance companies and usually includes prescription drug coverage. If you choose Part C, you are still in the Medicare program, but the private plan handles your benefits instead of the government. You can switch between Original Medicare (Parts A and B) and Part C during the annual enrollment period (October 15 to December 7).

Special situations: government workers and railroad employees

Some government employees who did not pay Medicare taxes may not may have access to for free Part A at 65. If you worked for a federal, state, or local government and were covered by a pension instead of Social Security, you may fall into this category. You can still join Medicare Part B and Part D, but you will have to pay the full premium for Part A if you want it.

Railroad employees who worked for a railroad company before 1983 may have different rules. The Railroad Retirement Board handles their benefits, and they may may have access to for Medicare through a different process. If you worked for a railroad, contact the Railroad Retirement Board directly to understand your coverage options.

Frequently Asked Questions

What happens if I miss my initial enrollment period?

If you miss the seven-month window around your 65th birthday and do not have other may have access to coverage, you will pay a permanent penalty on Part B and Part D premiums for as long as you have Medicare. The penalty is 10 percent of the standard premium for each 12 months you were late. You can still sign up during the general enrollment period (January 1 to March 31), but coverage does not start until July 1.

Can I get Medicare if I never worked?

If you never worked or did not work long enough to earn coverage yourself, you may be covered as the spouse or widow of someone who did work long enough. You must be at least 62 (or any age if you are caring for a child under 16). If you do not may have access to as a spouse, you can buy Part A and Part B by paying monthly premiums, though the cost will be higher than standard.

Do I have to sign up for all four parts of Medicare?

No. Part A is automatic at 65 if you may have access to. You must actively sign up for Part B and Part D during your enrollment period. Part C is optional and replaces Parts A and B if you choose it. You can have Part A and B without Part D, though you may face a penalty if you join Part D later without may have access to coverage.

What if I am still working at 65?

You can stay on your employer's health plan and delay Medicare without penalty, as long as your employer has 20 or more employees. Once you leave the job or lose coverage, you have eight months to sign up for Medicare. If you are self-employed or your employer has fewer than 20 employees, you should sign up for Medicare at 65 even if you are still working.

Can I switch from Medicare Advantage back to Original Medicare?

Yes, during the annual enrollment period (October 15 to December 7) you can switch from Part C (Medicare Advantage) to Original Medicare (Parts A and B). You can also sign up for Part D at the same time. Outside this window, you can only switch if you have a may have access to life event, such as moving out of your plan's service area or losing other health coverage.