When You Can Register for Medicare: Age, Work History, and Special Circumstances

You can register for Medicare starting at age 65, or earlier if you have a disability or end-stage renal disease

Medicare registration opens three months before the month you turn 65. If you were born on June 15, the window opens March 1. You can register during this window, or wait until after your birthday—but waiting costs you. If you miss your initial registration window and do not have coverage through an employer, Medicare charges a permanent penalty on your premiums.

You do not have to be retired to register. You can work full-time and still sign up at 65. The only limit is that if you earn above a certain amount while collecting Social Security before your full retirement age, your benefits are reduced—but that is a Social Security rule, not a Medicare one.

If you are under 65, you may be able to register earlier if you have been receiving Social Security Disability Insurance (SSDI) for 24 months, or if you have end-stage renal disease or ALS (amyotrophic lateral sclerosis). These are the only paths to Medicare before 65.

Key Takeaways

You can register for Medicare three months before the month you turn 65, and you should do so during this window to avoid permanent premium penalties.
If you are still working at 65 and have employer health coverage, you may be able to delay Medicare Part B without penalty, but you must understand your employer's coverage rules first.
If you have received SSDI for 24 months, you become may be able to access for Medicare at that point, regardless of your age.
People with end-stage renal disease or ALS can register for Medicare before age 65 through a separate process.

The three-month window before you turn 65

Medicare's initial enrollment period (IEP) is seven months long: three months before the month you turn 65, the month itself, and three months after. You can register during any of these seven months without penalty. Most people register during the three-month window before their birthday because it gives Medicare time to process your process and have coverage start on your birthday month.

If you register in the month you turn 65, your coverage typically starts the first day of that month. If you register in the three months after your birthday, your coverage starts the first day of the month after you register. The later you register, the longer you go without coverage—and the more you pay out of pocket.

You can register online through Medicare.gov, by phone at 1-800-MEDICARE, or in person at your local Social Security office. Online registration is usually fastest.

What happens if you miss the window

If you do not register during your seven-month initial enrollment period, you enter what Medicare calls a "general enrollment period" (GEP). General enrollment runs January 1 through March 31 each year. You can register then, but your coverage does not start until July 1 of that year—a gap of up to six months.

More importantly, Medicare adds a 10 percent permanent penalty to your Part B premium for each full year you were may be able to access but not enrolled. If you were may be able to access at 65 and did not register until age 68, that is three years of penalties—30 percent added to your premium for life. Part D (prescription drug coverage) has a similar penalty: 1 percent per month of delay.

The only exception is if you had creditable coverage through an employer or a spouse's employer. If your employer's health plan covers you at 65, you can delay Medicare Part B without penalty—but you must enroll within eight months of losing that coverage or retiring, whichever comes first. You still need to register for Part A (hospital insurance) at 65 even if you delay Part B.

Registering early if you have a disability

If you receive Social Security Disability Insurance (SSDI), you automatically become may be able to access for Medicare after you have been on SSDI for 24 months. You do not have to wait until 65. You do not have to explore separately—Social Security will contact you when you become may be able to access and walk you through registration.

The 24-month clock starts the month your disability benefits begin, not the month you applied. If you were approved for SSDI in March 2022, you become may be able to access for Medicare in March 2024. Social Security sends you information about three months before that date.

If you have end-stage renal disease (ESRD) or ALS, the rules are different. You can register for Medicare when ready upon diagnosis, without waiting for age 65 or the 24-month SSDI period. Your doctor or dialysis center can help you start the registration process.

Registering if you are still working at 65

You can register for Medicare while you are still employed. Your age is what matters, not your job status. However, if your employer has 20 or more employees and offers health coverage, you may have the option to delay Part B without penalty.

This is important: delaying Part B is optional, and the rules are strict. You can delay only if you are actively employed and covered under your employer's plan. If you are on unpaid leave, or if your employer's plan does not cover you (for example, you are a contractor), you cannot delay. You must enroll in Part B within eight months of losing your job or your employer coverage, or you will face penalties.

Part A (hospital insurance) has no penalty for delay if you have employer coverage, but most people register for it anyway since there is no cost if you have 40 quarters of work history.

How to register and what you will need

You will need your Social Security number, birth certificate or passport, and proof of citizenship or legal residency. If you are registering online at Medicare.gov, you can create a Medicare.gov account and complete the form yourself. If you register by phone (1-800-MEDICARE), a representative will walk you through the questions.

If you are registering through Social Security (because you are already receiving Social Security benefits), you may be able to register for Medicare at the same time. Ask when you call or visit.

Processing usually takes two to four weeks. Medicare will send you a Medicare card in the mail. Keep it safe—you will need it to show providers and pharmacies.

Special situations: Spouses, non-citizens, and people living abroad

If you are married, your spouse can register independently at their own age 65. You do not register together, and your spouse's registration does not affect yours.

If you are a non-citizen, you must have been a permanent resident (green card holder) for at least five years and be age 65 or older. Undocumented immigrants are not may be able to access for Medicare. If you are unsure of your status, call 1-800-MEDICARE and ask to speak with someone who handles non-citizen cases.

If you live outside the United States, you can still register for Medicare Part A (hospital insurance) at 65 if you have 40 quarters of work history. Part B and Part D have restrictions for people living abroad—you must return to the U.S. for at least two months per year to keep Part B active. Call 1-800-MEDICARE to discuss your situation if you live overseas.

Frequently Asked Questions

What if I turn 65 but am not yet receiving Social Security?

You can still register for Medicare independently. You do not have to be receiving Social Security benefits to sign up for Medicare. Register online at Medicare.gov or call 1-800-MEDICARE. You will need your Social Security number and proof of citizenship, but you do not need to have filed a Social Security claim yet.

Can I register for Medicare before I turn 65 if I am not disabled?

No. The only ways to register before 65 are if you have received SSDI for 24 months, or if you have end-stage renal disease or ALS. If you are under 65 and do not fall into one of these categories, you must wait until your initial enrollment period begins three months before your 65th birthday.

What is the penalty if I miss my enrollment window?

Medicare adds a 10 percent permanent penalty to your Part B premium for each full year you were may be able to access but not enrolled. Part D (prescription drugs) charges 1 percent per month of delay. These penalties stay on your premiums for as long as you have Medicare. The only way to avoid them is to register during your initial enrollment period or to have had creditable employer coverage.

Do I have to register for all four parts of Medicare at once?

No. You can register for Part A and Part B together, but Part D (prescription drugs) is separate. You can enroll in Part D during your initial enrollment period, or during the annual enrollment period (October 15 to December 7 each year). If you do not take a prescription drug plan when you first become may be able to access and later want one, you will face a penalty unless you had creditable coverage elsewhere.

What if my birthday is on the first of the month?

Your initial enrollment period still begins three months before that month. If you were born on June 1, your window opens March 1. The month of your birthday is counted as one of the seven months, not as an extra month.

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.