Medicare Eligibility Age: 65, and the Three Ways In Earlier
Medicare starts at 65 for most people who are U.S. citizens or have been legal permanent residents for at least 5 years. You can qualify earlier in three cases. (Medicare.gov: when coverage starts)
- Disability: after receiving Social Security disability benefits for 24 months.
- ALS: from the month disability benefits begin.
- End-stage renal disease: permanent kidney failure needing dialysis or a transplant.
Premium-free Part A needs 40 work quarters on your or your spouse's record; Part B costs $202.90 a month in 2026 for most people (CMS).
Medicare Initial Enrollment Period: Start Dates for Every Month
Your Initial Enrollment Period is seven months long, centered on the month you turn 65. The month you sign up decides when coverage starts:
| You sign up in | Coverage starts |
|---|---|
| 3, 2 or 1 month before your birthday month | The 1st of your birthday month |
| Your birthday month | The 1st of the next month |
| 1, 2 or 3 months after | The 1st of the month after you sign up |
Born on the 1st? Medicare treats you as turning 65 the month before, so the whole window shifts one month earlier. The calculator handles that automatically.
Still working at 65?
If you or your spouse have health coverage from current work at an employer with 20 or more employees, you can delay Part B without penalty and sign up within 8 months after the job or coverage ends. COBRA and retiree plans don't count as current work. Miss the window and the Part B late enrollment penalty applies for life (Medicare.gov: penalties).
Our take: sign up before your birthday month
Unless large-employer coverage is keeping you on the job plan, sign up in the three months before your birthday month: no gap, no penalty, no rush. That also starts your Medigap open enrollment period. Funding an HSA? Check your HSA stop date first. Covered at work? See Do I Have to Take Medicare at 65? The Employer-Plan Rules.