Medicare Eligibility

The three ways to become eligible

Pathway	When coverage can start
Age 65	The first day of your 65th-birthday month (earlier if your birthday is the 1st)
Disability	Month 25 of Social Security Disability Insurance payments
ALS (Lou Gehrig's disease)	The month SSDI benefits begin — no 24-month wait
End-stage renal disease	Generally the fourth month of dialysis, sooner with a home-dialysis programme or transplant

You must also be a U.S. citizen or a lawfully present permanent resident who has lived here for at least five continuous years. The official rules are on Medicare.gov and Social Security.

Work credits and what they actually determine

This is the distinction people most often get backwards. Work credits do not determine whether you're eligible for Medicare — they determine whether Part A is free.

• 40+ quarters (about 10 years) — Part A at no premium.
• 30–39 quarters — Part A costs $311 a month in 2026.
• Under 30 quarters — Part A costs $565 a month in 2026.

You can qualify on a spouse's record, including a former spouse if the marriage lasted at least 10 years, or a deceased spouse. Part B is available to everyone eligible at the standard premium regardless of work history. Figures from the CMS 2026 fact sheet.

Automatic enrolment vs signing up yourself

Whether you're enrolled automatically depends on whether you're already drawing Social Security.

• Already receiving Social Security or Railroad Retirement benefits at 65 — you're enrolled in Parts A and B automatically, and your card arrives about three months before your birthday month.
• Not yet drawing benefits — nothing happens automatically. You must sign up yourself through Social Security.
• Under 65 on SSDI — enrolment is automatic in month 25.

Because more people now delay Social Security past 65, assuming automatic enrolment is one of the most common and costly errors we see.

Eligibility if you're still working

You're eligible at 65 whether or not you're working. Whether you should enrol then is a different question, and it turns on the size of the employer.

Employer size	Who pays first	Practical effect
20 or more employees	The group plan pays first	You may safely delay Part B and get a Special Enrollment Period later
Fewer than 20 employees	Medicare pays first	You generally need Part B at 65 or risk large uncovered bills

Retiree coverage, COBRA, and marketplace plans do not count as active-employment coverage. See Medicare.gov on working past 65 and our enrollment periods guide.

Health Savings Accounts — the trap

You cannot contribute to an HSA once you're enrolled in any part of Medicare, including premium-free Part A. Worse, when you claim Social Security after 65, Part A is backdated up to six months, which can retroactively invalidate contributions you already made.

If you're contributing to an HSA and approaching 65, stop contributions at least six months before you plan to claim Social Security or enrol in Medicare. You can still spend the balance tax-free afterwards, including on Medicare premiums.

Eligibility for extra help with costs

Separate from Medicare eligibility, two income-based programmes decide what you actually pay.

• Medicare Savings Programs — pay the Part B premium and sometimes deductibles and coinsurance; see Medicare.gov. New Mexicans apply through the New Mexico Health Care Authority.
• Extra Help — eliminates the Part D premium and deductible and caps copays; apply at Social Security.

Qualifying for a Medicare Savings Program automatically qualifies you for Extra Help, and it also opens Special Enrollment Periods to change plans during the year.

Checking your own situation

Three questions answer it: what's your 65th birthday, are you drawing Social Security yet, and do you have coverage from active employment at an employer with 20 or more staff?

Our eligibility checker works through those, or read the enrollment periods next.

Not sure which of these fits you? A free 15-minute call with a licensed local advisor sorts it out — no pressure, and no cost to you. We do not offer every plan available in your area. For a complete list of every plan in your county, use Medicare Plan Compare or call 1-800-MEDICARE.

Special situations

Several circumstances follow their own rules, and they're the ones most often got wrong.

• End-stage renal disease — coverage generally begins the fourth month of dialysis, or the first month if you take part in a home-dialysis training programme. It can begin the month of a kidney transplant.
• ALS — no 24-month waiting period; Medicare starts the month SSDI benefits begin.
• Returning to work after disability — Medicare can continue for a period even after benefits stop, which protects people testing a return to employment.
• Lawful permanent residents — five continuous years of residence is required before you can enrol, and you may buy Part A if you lack work credits.
• Living abroad — Medicare generally doesn't cover care outside the United States, but Part B late penalties still accrue if you decline it, so the decision needs care.
• Incarceration — Medicare doesn't pay while you're in custody, but premiums and penalties continue to matter on release.

If any of these describes you, confirm the detail with Social Security rather than a general guide — including this one.

Checking your work credits and your record

You can confirm your own position rather than guessing at it. A free Social Security account at ssa.gov shows your recorded earnings, your accumulated credits, and your estimated benefits.

Two things are worth checking well before 65. First, that your earnings record is complete — gaps do happen, particularly with name changes, self-employment, or employers who no longer exist, and correcting one is far easier with old W-2s or tax returns in hand than decades later. Second, how many quarters you actually have, because that determines whether Part A is free or costs you a monthly premium.

If you're short of 40 quarters and still working, continuing to work may be worth more than it appears: reaching 40 converts a monthly Part A premium into no premium at all, for life.

If you are helping a parent

A large share of the eligibility questions we field come from adult children rather than the beneficiary. A few things make that easier.

You cannot act on someone else's behalf with Social Security or Medicare without authorisation — a signed form, a power of attorney, or being an appointed representative. Getting that in place before it's needed saves considerable frustration later, particularly if cognition is declining.

Practically, the useful things to establish early are: whether the parent is drawing Social Security yet, whether they have 40 work quarters or could qualify on a spouse's record, whether they have employer or retiree coverage, and whether their income is low enough for a Medicare Savings Program. That last question is the one most often skipped and the one most likely to save real money.