When Medicare Starts: Age Requirements and Enrollment Deadlines

Medicare begins at age 65 for most people

You become may be able to access for Medicare on the first day of the month you turn 65. If your birthday is the first of any month, that is your Medicare start date. If your birthday falls on any other day, Medicare begins on the first day of the following month.

You do not have to wait until you turn 65 to sign up — in fact, you should not. The enrollment window opens three months before the month you turn 65 and closes three months after. Missing this window can cost you money in the form of late enrollment penalties that stay with you for life.

Some people become may be able to access before 65. If you have received Social Security disability benefits for 24 months, or if you have end-stage renal disease or ALS (amyotrophic lateral sclerosis), you can enroll in Medicare regardless of age.

Key Takeaways

Medicare may be able to access begins the first day of the month you turn 65, but you should enroll three months before that date.
Your enrollment window is seven months long: three months before, the month of, and three months after you turn 65.
Waiting to enroll after your window closes results in permanent late enrollment penalties on your Part B and Part D premiums.
Some people under 65 can enroll if they have received disability benefits for 24 months, have end-stage renal disease, or have ALS.
You can enroll online at Medicare.gov, by phone at 1-800-MEDICARE, or in person at your local Social Security office.

The enrollment window: when to sign up

Your Initial Enrollment Period lasts seven months total. It starts three months before the month you turn 65 and ends three months after. For example, if you turn 65 in June, you can enroll from March through September.

You should enroll during the first three months of this window — before you turn 65 — so that your coverage starts on your 65th birthday. If you enroll after you turn 65, there may be a gap before your coverage begins, and you could face penalties.

If you miss your Initial Enrollment Period, you can still enroll during the General Enrollment Period, which runs from January 1 to March 31 each year. However, coverage does not start until July 1, and you will owe late enrollment penalties unless you had a may have access to reason for the delay.

Late enrollment penalties and how they work

If you do not enroll in Part B during your Initial Enrollment Period and you do not have a may have access to reason for the delay, you will pay a penalty for as long as you have Medicare. The penalty is 10 percent of the standard Part B premium for each full 12-month period you were not enrolled.

Part D (prescription drug coverage) has a similar penalty. If you go 63 days or more without drug coverage and you do not have a may have access to reason, you pay a penalty calculated based on the national average drug plan premium at the time you enroll.

These penalties do not go away. Even if you enroll years later, the penalty stays on your monthly bill. The only way to avoid them is to enroll on time or to have a may have access to reason — such as group health coverage through an employer, active military service, or certain life events like losing other coverage.

What counts as a may have access to reason to delay enrollment

You can delay enrollment without penalty if you have creditable coverage — health insurance through an employer, a spouse's employer, TRICARE, the Veterans Health Administration, or certain other sources. You must show proof of this coverage when you enroll.

If you are still working and your employer has 20 or more employees, your employer's health plan is usually creditable. You can stay on that plan and delay Medicare enrollment without penalty. Once you leave that job or lose that coverage, you have eight months to enroll in Medicare without penalty.

Other may have access to reasons include being a federal employee with coverage, receiving coverage through a union, or having coverage through a state or local government employer. Ask your current insurance provider whether your plan is creditable before you turn 65.

How to enroll in Medicare

You can enroll online at Medicare.gov using your personal computer or phone. You will need your Social Security number and information about your current health coverage. The online process takes about 15 minutes and you receive confirmation when ready.

You can also call 1-800-MEDICARE (1-800-633-4227) to enroll by phone. Representatives are available Monday through Friday, 8 a.m. to 8 p.m. Eastern time, and Saturday 9 a.m. to 1 p.m. Eastern time. Have your Social Security number and current insurance information ready.

If you prefer to enroll in person, visit your local Social Security office. You can find the nearest office at ssa.gov or by calling 1-800-772-1213. Bring your Social Security card, proof of citizenship or legal residency, and proof of your current health coverage if you have it.

What happens if you delay enrollment past your window

If you miss your Initial Enrollment Period, you are not locked out of Medicare forever. You can enroll during the General Enrollment Period (January 1 to March 31 each year), and your coverage will start July 1 of that year.

However, you will owe late enrollment penalties unless you had a may have access to reason for the delay. You will also have a gap in coverage from when your Initial Enrollment Period ended until July 1 when your new coverage starts. During this gap, you are responsible for all medical costs.

If you have a may have access to reason — such as losing employer coverage or moving to a new state — you may be able to enroll outside the normal windows. Contact Medicare directly to explain your situation and ask whether you may have access to for a Special Enrollment Period.

Medicare may be able to access for people under 65

You can enroll in Medicare before age 65 if you have received Social Security disability benefits (SSDI) for 24 consecutive months. Your Medicare coverage begins on the 25th month of your disability benefits, regardless of your age.

You are also may be able to access at any age if you have end-stage renal disease (ESRD) — permanent kidney failure requiring dialysis or a transplant. You must enroll within three months of learning you have ESRD, or you may face late enrollment penalties.

If you have ALS (amyotrophic lateral sclerosis), you become may be able to access for Medicare when ready upon diagnosis. You do not have to wait for disability benefits to be approved. Enroll as soon as you receive your diagnosis.

Questions to ask your doctor or Social Security office

Before you turn 65, ask your current doctor whether they accept Medicare. If you see a specialist, ask the same question. This helps you understand whether you need to change providers when you switch to Medicare.

Ask your employer's benefits department whether your health plan is creditable and what happens to your coverage when you retire. If you are still working at 65, ask whether you can stay on the employer plan and delay Medicare without penalty.

If you have questions about your specific situation — such as whether you have a may have access to reason to delay, or whether you owe late enrollment penalties — call Social Security at 1-800-772-1213 or Medicare at 1-800-MEDICARE. Both agencies can review your record and give you a clear answer.

Frequently Asked Questions

What if I turn 65 but I am still working?

You can delay Part B enrollment without penalty if your employer has 20 or more employees and you are covered by their health plan. You must enroll within eight months of leaving that job or losing that coverage. Part A (hospital insurance) has no premium, so many people enroll in Part A on time and delay Part B.

Do I have to enroll in all four parts of Medicare at once?

No. Part A (hospital) and Part B (medical) are separate from Part D (drugs) and Medigap or Medicare Advantage plans. You can enroll in Part A and Part B during your Initial Enrollment Period and add Part D later, though waiting on Part D will cost you a penalty. Talk to Medicare about which parts you need.

What if I miss my enrollment window by a few weeks?

Late enrollment penalties explore if you enroll after your seven-month window closes, even by one day, unless you have a may have access to reason. The penalty is permanent and increases the longer you wait. Contact Medicare when ready to see whether your situation qualifies for a Special Enrollment Period.

Can I change my mind after I enroll?

Yes, but only during certain times. You have until March 31 of the year after you first enroll to make changes. After that, you can change plans only during the Annual Enrollment Period (October 15 to December 7 each year) or if you have a may have access to life event.

Do I need to enroll if I am receiving Social Security?

Not automatically. Social Security does not enroll you in Medicare on your behalf. You must enroll yourself, even if you are already receiving Social Security benefits. Enroll online at Medicare.gov, by phone, or at your local Social Security office during your Initial Enrollment Period.

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.