When You Can Start Medicare: Age, Work Status, and Special Cases

You can start Medicare at 65, or earlier if you have a disability or end-stage renal disease

The standard age to start Medicare is 65. You do not have to be retired — you can still be working — but you become may be able to access for Part A (hospital insurance) and Part B (medical insurance) the month you turn 65. If you were born on the first of the month, your coverage starts the month before. Otherwise it starts the month of your birthday.

You can also start Medicare before 65 in two situations: if you have been receiving Social Security disability benefits for 24 months, or if you have end-stage renal disease (permanent kidney failure requiring dialysis or transplant). People with ALS (amyotrophic lateral sclerosis) can start when ready upon approval for disability, without waiting 24 months.

The month you become may be able to access is not the same as the month you must enroll. There is a window to sign up, and missing it can cost you. The rules differ depending on whether you have other health coverage through work.

Key Takeaways

You become may be able to access for Medicare the month you turn 65, even if you are still working and have employer health insurance.
If you have employer coverage through your own job (not your spouse's), you can delay Part B enrollment without penalty as long as you stay employed and covered.
If you miss your enrollment window, you pay a permanent penalty on Part B and Part D premiums — 10 percent per year of delay, for life.
You can enroll during your Initial Enrollment Period (the three months before, the month of, and three months after your 65th birthday), or during General Enrollment (January 1 to March 31 each year, with coverage starting July 1).
People receiving Social Security disability benefits automatically get Medicare after 24 months; those with ALS or end-stage renal disease can start sooner.

The three-month enrollment window around your 65th birthday

Your Initial Enrollment Period runs for seven months: three months before the month you turn 65, the month you turn 65, and three months after. During this window, you can enroll in Part A and Part B without penalty, even if you do not need coverage right away.

If you enroll before your 65th birthday, your coverage starts the month you turn 65. If you enroll during the month of your birthday or after, there is a one-month delay — so if you enroll in the month after your birthday, coverage starts two months later. This matters if you are leaving employer coverage and need no gap.

The safest approach is to enroll during the month you turn 65 or the month before. This ensures coverage starts on time and you avoid confusion about effective dates.

When you have health insurance through your job

If you are still working and your employer offers health coverage, you have more time to decide about Part B. You can delay Part B enrollment without penalty as long as you have creditable coverage — health insurance through your current employer based on your own employment. Creditable coverage through a spouse's job does not give you this protection.

Once you leave that job or lose the coverage, you have eight months to enroll in Part B without penalty. This is called your Special Enrollment Period. If you miss this window, you pay a 10 percent penalty on your Part B premium for each year you delayed — and that penalty is permanent, added to every premium for the rest of your life.

You still must enroll in Part A at 65, even if you delay Part B. Part A has no premium if you or your spouse paid Medicare taxes for 10 years, so there is no financial reason to wait, and delaying does not trigger a penalty.

Disability before age 65

If you receive Social Security Disability Insurance (SSDI) or Railroad Retirement Board disability benefits, you become may be able to access for Medicare after you have been receiving those benefits for 24 months. You do not have to wait until 65.

Medicare starts automatically — you do not have to enroll. Social Security will send you a Medicare card about three months before your 24-month mark. If you do not receive it, contact Social Security to confirm your Medicare start date.

If you have ALS, the 24-month wait is waived. You become may be able to access the month Social Security approves your disability claim. End-stage renal disease also bypasses the wait: you become may be able to access the month your kidney disease is diagnosed, if you need dialysis or a transplant, or the month after a transplant.

What happens if you miss your enrollment window

If you do not enroll in Part B during your Initial Enrollment Period and you do not have creditable coverage through an employer, you pay a penalty. The penalty is 10 percent of the standard Part B premium for each full 12 months you were may be able to access but not enrolled. That percentage is added to your premium permanently.

For example, if you turn 65 in January 2024 and do not enroll until January 2026 (24 months late), you pay a 20 percent penalty on your Part B premium for the rest of your life. The same rule applies to Part D (prescription drug coverage) — 1 percent per month of delay.

You can enroll during General Enrollment (January 1 to March 31 each year) if you miss your Initial Enrollment Period, but the penalty applies and coverage does not start until July 1. This is a much slower and more expensive route than enrolling on time.

How to enroll and what you need

You can enroll online at Medicare.gov, by phone at 1-800-MEDICARE (1-800-633-4227), by mail, or in person at your local Social Security office. Online enrollment is fastest — you can complete it in about 10 minutes if you have your Social Security number and information about any current health coverage.

You will need your Social Security number, date of birth, and citizenship or immigration status. If you are still working, have the name and address of your employer and the dates you were covered under their health plan. If you are enrolling in Part D (prescription drug coverage) at the same time, have a list of your current medications or your pharmacy's phone number.

Enrollment is open year-round for people turning 65 or becoming may be able to access due to disability. If you miss your Initial Enrollment Period, you can enroll during General Enrollment (January 1 to March 31), but coverage does not start until July 1 and penalties explore.

Special cases: Non-citizens and people living abroad

You must be a U.S. citizen or a lawful permanent resident (green card holder) to enroll in Medicare. If you are a lawful permanent resident, you must have lived in the United States for at least five consecutive years before you turn 65. Temporary visa holders, undocumented immigrants, and people on other non-immigrant visas cannot enroll.

If you are a U.S. citizen living abroad, you can still enroll in Medicare at 65. You can use Medicare in the United States and in some situations abroad, but coverage is limited outside U.S. borders. Contact Medicare directly to discuss your situation if you live overseas or plan to move.

Frequently Asked Questions

Do I have to enroll in Medicare if I am still working at 65?

You do not have to enroll in Part B if you have creditable health coverage through your current job. You must enroll in Part A (it is free if you paid Medicare taxes for 10 years), but you can delay Part B without penalty as long as you stay employed and covered. Once you leave that job, you have eight months to enroll in Part B.

What if I turn 65 but do not want Medicare yet?

If you have employer coverage, you can delay Part B. If you do not have other coverage, you can still enroll during your Initial Enrollment Period and choose a start date. You cannot refuse Medicare entirely at 65 — you can only delay Part B if you have creditable coverage through work.

Can I enroll in Medicare online?

Yes. Go to Medicare.gov and click "Sign Up for Medicare." You will need your Social Security number, date of birth, and information about any current health coverage. Enrollment takes about 10 minutes. You can also call 1-800-MEDICARE or visit a Social Security office.

What if I was approved for disability but have not received benefits for 24 months yet?

You become may be able to access for Medicare 24 months after your first disability benefit payment, not 24 months after approval. Social Security will notify you when you reach that mark. If you have ALS, you become may be able to access when ready upon approval.

Do I lose Medicare if I go back to work?

No. Once you are enrolled in Medicare, you keep it even if you return to work or earn income. You can have both Medicare and employer coverage at the same time. If you are still working and turn 65, you can keep your employer plan and add Medicare, or drop the employer plan and use Medicare alone.

This guide is for general information only and is not medical, financial, legal, or other professional advice. For decisions specific to your situation, consult a qualified professional. See our Editorial Policy.