Quick answer
You’re eligible for Medicare if you’re 65 or older and a U.S. citizen or a permanent resident who has lived here for at least five years in a row. People under 65 qualify after 24 months of Social Security disability benefits, or right away with ALS or kidney failure that needs dialysis or a transplant. Most people get Part A without a premium because they or a spouse worked and paid Medicare taxes for about 10 years.
Key takeaways
- At 65, sign up during a seven-month window that starts three months before your birthday month. If you already get Social Security, you’re enrolled automatically.
- Part A (hospital) is premium-free for most people. Part B (medical) costs $202.90 a month in 2026 for most people.
- If you have job-based coverage from current work, you can delay Part B without a penalty and sign up within eight months after that coverage ends.
- Signing up late without other coverage means a Part B penalty of 10% for each full year you went without it, for as long as you have Part B.
- Medicare is different from Medicaid, which is based on income, though some people qualify for both.
On this page
Who qualifies
- Age 65 or older, and a U.S. citizen or a lawful permanent resident who has lived in the U.S. for at least five consecutive years. See health insurance if you’re not a U.S. citizen.
- Under 65 with a disability, after receiving Social Security disability or certain Railroad Retirement disability benefits for 24 months.
- ALS, as soon as your disability benefits start.
- End-stage renal disease, meaning permanent kidney failure that requires dialysis or a transplant.
Medicare is a federal program, part of the government health insurance system along with Medicaid and CHIP.
The parts of Medicare
- Part A, hospital insurance: inpatient hospital stays, skilled nursing facility care after a hospital stay, hospice and some home health care. The 2026 deductible is $1,736 per benefit period.
- Part B, medical insurance: doctor visits, outpatient care, preventive services, lab tests, imaging like MRIs and X-rays, and medical equipment. The 2026 premium is $202.90 a month for most people, with a $283 deductible and usually 20% coinsurance after that.
- Part C, Medicare Advantage: private plans that replace Original Medicare and usually include drug coverage and extras, with a network and prior approval rules. You can switch plans each fall during Medicare open enrollment.
- Part D, drug coverage: prescription drug plans from private insurers. Out-of-pocket drug costs are capped at $2,100 in 2026 and $2,400 in 2027.
- Medigap: private supplement plans that help pay Original Medicare’s deductibles and coinsurance.
Do you pay for Part A?
Most people don’t. You get premium-free Part A if you or your spouse worked and paid Medicare taxes for at least 40 quarters, about 10 years. Otherwise, you can buy Part A for $311 or $565 a month in 2026, depending on how long you worked.
When to sign up
| Situation | When to enroll |
|---|---|
| Turning 65 | During the 7-month initial enrollment period: the 3 months before your birthday month, that month, and the 3 months after |
| Already getting Social Security at 65 | Automatic; your card arrives about 3 months before your birthday |
| Working with job-based coverage after 65 | Within 8 months after the job or the coverage ends, whichever comes first |
| Missed your window | General enrollment, January 1 to March 31, with possible penalties |
Coverage starts the first day of your birthday month if you sign up in the three months before it. If you sign up later, it starts the month after you sign up.
If you work for an employer with 20 or more employees, you can usually keep that coverage and delay Part B. COBRA and retiree coverage don’t count as coverage from current work, so don’t delay Part B because of them.
Penalties for signing up late
- Part B: 10% more for each full 12-month period you could have had Part B but didn’t, added to your premium for life.
- Part D: a penalty based on how long you went without creditable drug coverage after your initial enrollment period.
- Part A: if you have to buy it, 10% more for twice the number of years you delayed.
Medicare vs. Medicaid
Medicare is based mainly on age or disability. Medicaid is based on income. People with low incomes and limited savings can have both, and programs like Medicare Savings Programs and Extra Help lower Medicare premiums and drug costs.
Choosing coverage
Most people choose between Original Medicare with a Medigap plan and a Part D plan, or a Medicare Advantage plan. Compare plans on costs, doctors and drug coverage. For more on coverage after 65, see health insurance for the elderly, and if cost is the main concern, the cheapest ways to get health insurance.
Related guides: working past 65, Medicare late enrollment penalties and the Medicare Part B premium and IRMAA.
Not 65 yet and need coverage until then? Compare plans in your ZIP code.
Frequently asked questions
Am I automatically enrolled in Medicare at 65?
Only if you’re already getting Social Security or Railroad Retirement benefits. Otherwise, you need to sign up.
Can I get Medicare before 65?
Yes, after 24 months of Social Security disability benefits, or sooner if you have ALS or end-stage renal disease.
Does my spouse get Medicare when I do?
No. Each person qualifies on their own at 65 or through disability. A spouse under 65 needs other coverage; see what happens to my wife’s health insurance when I go on Medicare.
Can I keep my marketplace plan after I get Medicare?
You can, but once you’re eligible for premium-free Part A, you lose any premium tax credit. Most people end their marketplace plan when Medicare starts.
Sources
This article is general information, not legal or insurance advice. Medicare rules have exceptions, so check with Medicare.gov, Social Security or your State Health Insurance Assistance Program (SHIP) for your situation. Last reviewed September 2026.