People are generally eligible to enroll in Medicare when they turn 65 years old. However, certain exceptions mean you must pay extra premiums or may not be eligible to enroll, even at 65 years old.
To qualify for premium-free Medicare Part A, you or your spouse must have worked for 40 quarters (around 10 years) and paid Medicare tax.
You can still sign up for Part A if you haven’t worked long enough. However, you have to pay a monthly premium. In 2025, you must pay $285 or $518, depending on how long you or your spouse has worked.
Even if you’re 65 years or older, you still may not be eligible for Medicare unless you’re also a U.S. citizen or have been a lawful U.S. resident for at least 5 years.
If you don’t meet either of these requirements, you won’t be eligible for Medicare and must purchase health coverage elsewhere.
If you’re not eligible for premium-free Medicare Part A and can work past 65 years old, you may earn enough work history to qualify for premium-free Part A.
If you’re still working when you turn 65 years old and have health insurance through your employer, you can delay your enrollment without paying late penalty fees.
Sign up for Medicare before your employer insurance ends to avoid a gap in your coverage. You may also be able to enroll in Medicare if your employer insurance changes.