Eligibility
Most people get one window. It is worth knowing where yours sits.
Medicare eligibility is not complicated, but it is unforgiving about dates. Start with your birthday and work outwards.
Start here
Your Initial Enrollment Period.
Seven months around your 65th birthday: three before, the month itself, three after. Enter a date and we will name the exact first and last day.
Work out your window
Nothing is sent anywhere. The arithmetic runs in your browser and stops there.
Your Initial Enrollment Period is seven months long: the three months before the month you turn 65, that month, and the three months after. If you were born on the first of a month, the whole window shifts one month earlier.
Every enrollment windowWho qualifies
Four doors into the same programme.
Age is the usual one. It is not the only one, and the other three have their own timetables.
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You are turning 65
The ordinary route. Your seven-month Initial Enrollment Period opens three months before your birthday month.
Everyone gets this one exactly once.
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You have had SSDI for 24 months
Medicare begins automatically in the 25th month of Social Security Disability Insurance payments, at any age.
No application needed. The card arrives.
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You have ALS
Medicare begins the same month your disability benefits begin. There is no 24-month waiting period.
The waiting period is waived in statute.
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You have end-stage renal disease
Eligibility at any age, usually from the fourth month of dialysis — earlier with home dialysis training or a transplant.
The timetable is specific. Get it checked.
Premium-free Part A
Forty quarters, and whose they are.
Part A is free of premium if you or your spouse paid Medicare payroll taxes for at least 40 quarters — ten years of work. It does not have to be your own record: a current spouse, a divorced spouse after a marriage of ten years or more, or a deceased spouse can all qualify you.
With fewer than 40 quarters you can still buy Part A, at a monthly premium CMS sets each year, with a reduced rate between 30 and 39 quarters. Part B always carries a premium, whatever your work history, and higher earners pay IRMAA on top of it based on the tax return from two years earlier.
- 40+ quarters
- Part A at no premium. The ordinary case.
- 30–39 quarters
- Part A at a reduced premium set annually by CMS.
- Under 30 quarters
- Part A at the full premium, if you buy in.
- Part B, always
- A monthly premium for everyone, plus IRMAA above the income threshold.
Still working at 65
The employee count decides everything.
If your employer has 20 or more employees, the group plan generally pays first and Medicare second. You can delay Part B without a penalty for as long as that coverage lasts, and pick it up through an eight-month Special Enrollment Period when it ends. Most people still take premium-free Part A.
If your employer has fewer than 20 employees, Medicare generally pays first and the group plan second. Delaying Part B in that situation can leave the group plan refusing the share Medicare would have paid. Confirm the employee count with HR before you decide anything at all.
A Health Savings Account adds one more rule: you cannot contribute to an HSA in any month you are enrolled in any part of Medicare, and Part A can be backdated up to six months when you enrol late. Stop contributions early enough to avoid a tax penalty.
Asked often
- At what age am I eligible for Medicare?
- Sixty-five for almost everyone. Your Initial Enrollment Period is seven months long — the three months before the month you turn 65, that month, and the three months after. If your birthday falls on the first of a month, Medicare treats you as turning 65 in the previous month and the whole window shifts one month earlier.
- Can I get Medicare before 65?
- Yes, in three situations. After 24 months of Social Security Disability Insurance payments you are enrolled automatically. With ALS you are enrolled the month your disability benefits begin, with no waiting period. With end-stage renal disease you may qualify at any age, on a timetable tied to dialysis or a transplant.
- Do I have to be a US citizen?
- No. Lawful permanent residents qualify, but if you have not paid Medicare taxes for 40 quarters you generally need five continuous years of residence before you can buy into Part A, and Part A will carry a premium.
- Am I enrolled automatically?
- If you are already receiving Social Security or Railroad Retirement Board benefits when you turn 65, you are enrolled in Parts A and B automatically and your card arrives about three months beforehand. If you are not yet claiming Social Security — increasingly common as people delay to 67 or 70 — nothing happens unless you apply. That is the single most common way people miss their window.
How to enrol
Three ways in, all through Social Security.
Medicare enrollment is administered by the Social Security Administration, not by an insurance company. Nobody should ever charge you for it.
Online
At ssa.gov, in about fifteen minutes. The fastest route, and the one that gives you a written receipt.
By phone
1-800-772-1213, TTY 1-800-325-0778. Expect a wait in the autumn.
In person
At a Social Security office, by appointment. Useful if your situation involves a spouse’s work record or a disability determination.
Choosing a plan is a separate step, and it comes after. Once Part A and Part B are in place you can compare the three routes, or ask us to do it with you.
If you are within a year of 65, this is the right time.
Not because anything is urgent, but because the decisions are easier to make slowly. Bring your birthday, your employer situation and your doctor list.