The Age When You Can Start Medicare Coverage

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

Medicare begins the month you turn 65, as long as you or your spouse paid Medicare taxes while working. You do not have to wait until your birthday month ends — coverage starts on the first day of that month. If you were born on the first of any month, your coverage begins the previous month.

You can also start Medicare before 65 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) or ALS (amyotrophic lateral sclerosis). These routes have different timing rules and require different paperwork.

The month you turn 65 is your Initial Enrollment Period — a seven-month window that starts three months before your birthday month and ends three months after. If you miss this window, you will face late-enrollment penalties on your premiums for as long as you have Medicare, unless you have a valid reason for the delay.

Key Takeaways

Medicare starts the first day of the month you turn 65, provided you or your spouse paid Medicare taxes for at least 10 years of work.
Your Initial Enrollment Period runs from three months before your 65th birthday month through three months after, and missing it triggers permanent premium penalties.
You can start Medicare before 65 if you have been on Social Security disability for 24 months, have end-stage renal disease, or have ALS.
You must actively enroll during your Initial Enrollment Period — Medicare does not start automatically even if you are already receiving Social Security.
If you are still working and have health coverage through your employer, you may be able to delay enrollment without penalty under certain conditions.

How the Initial Enrollment Period works

Your Initial Enrollment Period is seven months long and centers on the month you turn 65. It starts three months before that month and ends three months after. For example, if you turn 65 in June, your enrollment period runs from March through September.

You can enroll during any of these seven months. The Social Security Administration recommends enrolling in the three months before your birthday month so that coverage begins on time. If you enroll after your birthday month, there will be a gap in coverage, and you may owe back premiums.

Enrollment happens through Social Security, Medicare.gov, or by phone at 1-800-MEDICARE. You will need your Social Security number and information about any current health coverage. If you enroll by the 15th of any month, coverage typically begins the first day of the following month.

Starting Medicare before 65 due to disability

If you have been receiving Social Security Disability Insurance (SSDI) for 24 consecutive months, you become may be able to access for Medicare automatically. You do not need to be 65. The 24-month waiting period starts from the month Social Security approved your disability claim, not from when you first applied.

Medicare coverage begins in the 25th month of your disability benefits. You do not need to enroll — Social Security will transfer you to Medicare automatically. However, you should verify that the transfer happened by checking your Medicare.gov account or calling 1-800-MEDICARE about two months before the 25-month mark.

If you are receiving Supplemental Security Income (SSI) instead of SSDI, the rules are different. SSI recipients do not automatically may have access to for Medicare at 24 months. You will need to meet other conditions, such as being 65 or older, blind, or disabled under Medicare's own definition.

Starting Medicare with end-stage renal disease or ALS

You can start Medicare at any age if you have end-stage renal disease — meaning your kidneys no longer work and you need dialysis or a transplant. Coverage begins the first month you start dialysis treatment or the month you receive a kidney transplant, whichever comes first. If you are already on dialysis when you learn about Medicare, you can enroll retroactively.

If you have ALS (Lou Gehrig's disease), you become may be able to access for Medicare when ready upon diagnosis, regardless of age. You do not have to wait for Social Security to approve a disability claim. You will need medical documentation of your ALS diagnosis from your doctor.

For both conditions, you should enroll as soon as you receive your diagnosis or begin treatment. Contact Social Security or call 1-800-MEDICARE to start the process. Delays can create gaps in coverage and may result in late-enrollment penalties.

What happens if you miss your Initial Enrollment Period

If you do not enroll during your seven-month Initial Enrollment Period and you do not have a valid reason for the delay, you will face a late-enrollment penalty. This penalty increases your Part B premium (medical insurance) by 10 percent for each full year you were may be able to access but not enrolled. The penalty is permanent — it stays on your account for as long as you have Medicare.

A valid reason for missing the important date includes having health coverage through an active employer or a spouse's active employer. If you were covered by group health insurance while you were 65 or older, you may have an eight-month Special Enrollment Period after that coverage ends. During this window, you can enroll without penalty.

If you missed your Initial Enrollment Period and do not have a valid reason, you can still enroll during the General Enrollment Period, which runs January 1 through March 31 each year. Coverage would begin July 1 of that year. The penalty will explore unless you later may have access to for a Special Enrollment Period.

Working past 65 and delaying Medicare

If you are still working at 65 and have health coverage through your employer or your spouse's employer, you may be able to delay Medicare enrollment without penalty. This is called the working exception. You must have actual group health insurance through active employment — coverage from a retiree plan does not count.

To use the working exception, you must enroll in Medicare Part A (hospital insurance) when you turn 65, even if you do not enroll in Part B (medical insurance). Part A is usually free if you paid Medicare taxes, and enrolling protects you from penalties later. You can delay Part B enrollment as long as you remain covered by the employer plan and are still working.

Once you leave your job or lose the employer coverage, you have eight months to enroll in Part B without penalty. If you do not enroll within that window, the late-enrollment penalty applies. You should contact Social Security or Medicare about two months before you plan to retire to understand your options.

Documents and information you will need to enroll

To enroll in Medicare, have your Social Security number, birth date, and citizenship or immigration status ready. You will also need information about any current health coverage — the name of your employer or your spouse's employer, your group health plan number, and your policy number.

If you are enrolling due to disability or end-stage renal disease, you will need medical records or a letter from your doctor confirming your condition. For SSDI recipients, Social Security will have your information on file, so you may not need to provide additional documentation.

You can enroll online at Medicare.gov, by phone at 1-800-MEDICARE (1-800-633-4227), or in person at your local Social Security office. The online process takes about 10 minutes. Phone enrollment may take longer, especially during busy periods near the birthday month.

Frequently Asked Questions

Do I have to enroll in Medicare if I am still working and have employer coverage?

You must enroll in Part A (hospital insurance) at 65 to avoid penalties later, even if you delay Part B. If you have active employer coverage and are still working, you can delay Part B without penalty as long as you enroll within eight months of losing that coverage or retiring.

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

You can enroll in Medicare separately from Social Security. You do not have to claim Social Security benefits to start Medicare. Contact Medicare directly at 1-800-MEDICARE or enroll online at Medicare.gov during your Initial Enrollment Period.

Can I enroll in Medicare before my 65th birthday?

Yes, you can enroll starting three months before the month you turn 65. This is the earliest point in your Initial Enrollment Period. Enrolling early ensures coverage begins on the first day of your birthday month.

If I am on disability and turn 65, does anything change?

No. Your Medicare coverage continues without interruption. You will straightforward transition from disability-based Medicare to age-based Medicare on your 65th birthday, but your coverage and benefits remain the same.

What is the penalty if I enroll late?

The Part B late-enrollment penalty is 10 percent of the standard premium for each full year you were may be able to access but not enrolled. This penalty is added to your monthly premium permanently. The exact dollar amount changes each year based on the standard premium.

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.