Who Medicare covers
You are covered by Medicare if you are 65 or older, or if you are under 65 and have received Social Security Disability Insurance (SSDI) for at least 24 months, or if you have end-stage renal disease (ESRD) or amyotrophic lateral sclerosis (ALS). Most people do not need to do anything to find out — if you meet one of these conditions, you already know it, because it involves either your age or a diagnosis your doctor has made.
The confusion usually comes later: once you know you are covered, you still have to decide which parts of Medicare to join and when. That is a separate step from knowing whether you are covered at all.
If you are not sure whether you have SSDI or whether your condition qualifies, you can call Social Security at 1-800-772-1213 (TTY 1-800-325-0778) and ask. They will tell you whether your record shows you are receiving disability benefits and for how long.
Key Takeaways
- You are covered by Medicare at 65 regardless of your work history or income, as long as you or your spouse paid Medicare taxes for at least 10 years total.
- If you are under 65, you may be covered through SSDI (after 24 months), ESRD, or ALS, and your doctor or Social Security can confirm which applies to you.
- Knowing you are covered is different from signing up — you must enroll during your Initial Enrollment Period or face late penalties.
- Your state of residence does not change whether you are covered, but it does affect which plans are available to you.
- If you are still working at 65, you may not need to enroll right away, but you should check with your employer's benefits office about the timing.
The 10-year work history requirement
To receive Medicare Part A (hospital insurance) at 65 without paying a monthly premium, you or your spouse must have paid Medicare taxes for at least 10 years total — not necessarily consecutive. This means you worked in jobs where Medicare taxes were withheld from your paycheck, or you were self-employed and paid self-employment tax.
If you do not have 10 years of work history, you can still join Medicare Part A, but you will pay a monthly premium. The amount depends on how many years of coverage you do have. Social Security can tell you exactly how many years are on your record.
If your spouse worked for 10 years and you did not, you may still be covered without a premium based on their work history. You do not have to be married now — if you were married for at least 10 years and are now divorced, you may be covered on their record if you are 62 or older.
Coverage through disability before age 65
If you are under 65 and receiving SSDI, you become covered by Medicare automatically after you have been on SSDI for 24 months. You do not have to explore separately for Medicare — it starts on the 25th month of your SSDI benefits. Social Security will send you information about Medicare enrollment about three months before your coverage begins.
If you have ESRD (permanent kidney failure requiring dialysis or a transplant), you are covered by Medicare regardless of age, but the timing depends on whether you are working and whether you have already started treatment. Your nephrologist or dialysis center can tell you the exact date your coverage begins.
If you have been diagnosed with ALS (Lou Gehrig's disease), you are covered by Medicare when ready, without waiting for SSDI approval or any other condition. You will need to enroll during your Initial Enrollment Period, which begins the month you turn 65 or the month your disability or ESRD coverage would start.
When you must enroll
Your Initial Enrollment Period is the window when you can join Medicare without penalties. For most people, this is the three months before the month you turn 65, the month you turn 65, and the three months after. That is a seven-month window total.
If you are under 65 and covered through SSDI, ESRD, or ALS, your Initial Enrollment Period starts three months before your coverage would begin and runs for seven months, just like at 65.
If you miss this window, you can still join, but you will pay a late enrollment penalty for the rest of your life. The penalty is a percentage added to your monthly premium, and it increases for each year you delayed. For example, if you were supposed to join at 65 but did not join until 67, you would pay a penalty for two years of delay, and that penalty stays on your bill forever.
If you are still working at 65
If you are working and your employer has 20 or more employees, your employer's health insurance is the primary payer, and Medicare is secondary. In this case, you may be able to delay joining Medicare Part B (medical insurance) without a late penalty, as long as you enroll within eight months of leaving your job or losing your employer coverage.
You should still enroll in Part A at 65 if you are covered, because it is usually free and covers hospital stays. Check with your employer's benefits office about whether you should delay Part B, because the rules depend on your specific situation.
If your employer has fewer than 20 employees, Medicare becomes primary at 65, and you should enroll in both Part A and Part B during your Initial Enrollment Period.
How to confirm your coverage status
The most direct way is to create an account on ssa.gov (Social Security's website) and view your earnings record. This shows how many years of work history you have and whether you are currently receiving SSDI. You can also call Social Security at 1-800-772-1213 and ask an agent to review your record with you.
If you are approaching 65 and want to know your exact coverage date, you can also call Medicare directly at 1-800-MEDICARE (1-800-633-4227). They can tell you whether you are already in the system and when your coverage would begin.
If you have ESRD or ALS, your doctor or treatment center should have already discussed Medicare with you, but you can also ask them directly when your coverage begins and what you need to do to enroll.
What happens after you know you are covered
Knowing you are covered is the first step. The next step is deciding which parts of Medicare to join and when. Medicare has four parts — A (hospital), B (medical), C (Medicare Advantage, an alternative to A and B), and D (prescription drugs) — and you do not have to join all of them at once.
Most people join Part A and Part B during their Initial Enrollment Period. Part C and Part D are optional and have their own enrollment periods. If you have questions about which parts you need, you can speak with a Medicare counselor for free by calling 1-800-MEDICARE or visiting your local Area Agency on Aging.
Frequently Asked Questions
What if I worked outside the United States?
Work done in most countries does not count toward the 10-year requirement, even if you paid taxes. However, if you worked in a country that has a Social Security agreement with the United States, some of that work may count. Call Social Security at 1-800-772-1213 and ask whether your country has a totalization agreement.
Can I be covered by Medicare and still have my employer insurance?
Yes. If you are 65 and still working, you can have both. Your employer insurance is usually primary, and Medicare is secondary. Check with your employer's benefits office about how the two coordinate before you enroll.
Do I lose Medicare coverage if I move to another state?
No. Medicare coverage follows you anywhere in the United States. Your coverage does not change, but the plans available to you may differ by state. If you move, you can change your Medicare plan during the Annual Enrollment Period or within 60 days of moving.
What if I am not a U.S. citizen?
You must be a U.S. citizen or a lawful permanent resident who has lived in the United States for at least five years to be covered by Medicare. If you are not sure about your status, call Social Security at 1-800-772-1213 and ask whether you meet this requirement.
Can I check my SSDI status online?
Yes. Create an account at ssa.gov and sign in to view your benefits and earnings record. You can also call Social Security at 1-800-772-1213. Both methods will show you whether you are currently receiving SSDI and for how long.