Medicare starts 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, or the first day of the month after you turn 65, depending on your birthday. If you turn 65 on the first of any month, coverage begins that same day. If your birthday falls on any other day of the month, coverage begins on the first day of the following month.

You do not have to wait until you turn 65 to sign up. You can enroll starting three months before the month you turn 65. This three-month window is called your Initial Enrollment Period, and it lasts seven months total — three months before, the month you turn 65, and three months after.

If you miss this window and do not sign up when you first become may be able to access, you will face a permanent penalty on your monthly premiums. The penalty amount depends on how long you waited, and it stays with you for life, even if you sign up years later.

Key Takeaways

  • Medicare may be able to access begins at age 65, with coverage starting the first day of your birth month or the following month depending on your birthday.
  • Your Initial Enrollment Period runs for seven months — three months before you turn 65, the month you turn 65, and three months after.
  • Enrolling during your Initial Enrollment Period avoids a permanent late-enrollment penalty on your Part B and Part D premiums.
  • Some people under 65 may be may be able to access if they receive Social Security Disability Insurance (SSDI) for 24 months or have end-stage renal disease or ALS.
  • You must actively enroll in Medicare; it does not happen automatically even if you receive Social Security.

How to count your seven-month enrollment window

Your Initial Enrollment Period always spans seven months. To find your exact dates, start with the month you turn 65 and count backward three months and forward three months.

If you turn 65 in June, your enrollment window opens in March and closes in September. If you turn 65 in January, your window opens in October of the previous year and closes in April. The Social Security Administration website has a tool that shows your specific dates once you enter your birth date.

You can enroll online through Medicare.gov, by phone at 1-800-MEDICARE, by mail, or in person at your local Social Security office. Online enrollment is fastest — you can complete it in about 15 minutes if you have your Social Security number and information about your current health coverage.

What happens if you miss your enrollment window

If you do not sign up during your Initial Enrollment Period and you do not have a valid reason for the delay, you will pay a penalty for the rest of your life. For Part B (doctor visits and outpatient care), the penalty is 10 percent of the standard premium for each full 12-month period you were may be able to access but not enrolled. For Part D (prescription drugs), the penalty is 1 percent of the national average premium for each month you were not covered.

These penalties stack. If you waited two years to enroll, your Part B penalty would be 20 percent of the standard premium, added to your monthly bill permanently. The only way to avoid this penalty is to have had other creditable health coverage during the months you were not enrolled in Medicare — meaning coverage through an employer, a spouse's employer, or a government program that is at least as good as Medicare.

If you had creditable coverage and can prove it, you may be able to enroll without penalty even after your Initial Enrollment Period ends. You will need documents from your former employer or insurance company showing the dates you were covered.

People under 65 who may be may be able to access for Medicare

Most people do not become may be able to access until 65, but three groups can receive Medicare before that age. If you have received Social Security Disability Insurance (SSDI) for 24 consecutive months, you become may be able to access for Medicare at any age. The 24-month waiting period begins the month your disability benefits start, not the month you applied.

If you have end-stage renal disease (permanent kidney failure requiring dialysis or transplant), you may be may be able to access when ready, regardless of age. If you have ALS (amyotrophic lateral sclerosis, also called Lou Gehrig's disease), you become may be able to access when ready upon diagnosis, with no waiting period.

If you fall into one of these categories, you should contact Social Security or Medicare directly to confirm your may be able to access date. The rules for these groups differ slightly from standard age-based enrollment, and missing your window still carries penalties.

Medicare enrollment is not automatic

Even if you are already receiving Social Security retirement benefits, you must actively enroll in Medicare. Social Security does not automatically sign you up. If you do not enroll during your Initial Enrollment Period, you will need to wait for a future General Enrollment Period (January 1 to March 31 each year) or a Special Enrollment Period if you have a may have access to life event.

The General Enrollment Period carries the same late-enrollment penalties as missing your Initial Enrollment Period. A Special Enrollment Period may allow you to enroll without penalty if you had creditable coverage or experienced certain may have access to events like losing employer coverage or moving to a new state.

The difference between Part A and Part B enrollment

Medicare has two main parts that work differently during enrollment. Part A covers hospital stays, skilled nursing care, and hospice. Part B covers doctor visits, lab tests, and outpatient procedures. Most people do not pay a premium for Part A if they or their spouse paid Medicare taxes for at least 10 years while working.

Part B has a monthly premium that varies by income, and this is where the late-enrollment penalty applies if you miss your window. Part A generally does not carry a late-enrollment penalty unless you delayed enrollment and did not have creditable coverage. If you are still working at 65 and have health coverage through your employer, you may be able to delay Part B enrollment without penalty — but you must have creditable coverage and meet specific rules.

If you are unsure whether your employer coverage counts as creditable, contact your employer's benefits department or call Medicare at 1-800-MEDICARE before your Initial Enrollment Period ends.

Planning ahead: what to do before you turn 65

About three months before you turn 65, gather documents you will need to enroll: your Social Security number, information about any current health coverage, and your citizenship or immigration status. If you are not yet receiving Social Security benefits, you will need to set up a my Social Security account online or visit your local Social Security office.

Review your current coverage to understand whether it counts as creditable. If you are covered through an employer or union, ask your benefits department whether you can delay Medicare Part B without penalty. If you are self-employed or have individual insurance, you will likely need to enroll in Medicare Part B during your Initial Enrollment Period to avoid penalties.

If you have questions about your specific situation, call Medicare at 1-800-MEDICARE. Representatives can walk you through your options and confirm your enrollment window dates. This call takes about 15 minutes and can save you thousands in penalties over your lifetime.

Frequently Asked Questions

Can I enroll in Medicare before I turn 65?

Yes. You can enroll starting three months before the month you turn 65. If you turn 65 in September, you can enroll beginning in June. Enrolling early does not change your coverage start date — it will still begin the first day of your birth month or the following month — but it ensures you do not miss your enrollment window.

What if I am still working at 65?

You can delay Part B enrollment without penalty if you have health coverage through your current employer and you are actively working. You must enroll in Part A, but Part B can wait. When you leave your job or lose coverage, you have eight months to enroll in Part B without penalty. You will need to provide proof that you had creditable employer coverage.

Do I lose Medicare if I go back to work after 65?

No. Once you are enrolled in Medicare, your coverage continues even if you return to work or earn income. You can have both Medicare and employer coverage at the same time. Medicare becomes your primary insurance at 65 regardless of your employment status.

What if I was not a U.S. citizen for 10 years?

You may still be may be able to access for Part A at 65 if you have been a permanent resident for at least five years and are at least 65 years old. Part B has different rules. Contact Social Security or Medicare to discuss your specific citizenship history and what coverage you may be may have access to to.

Can I change my mind after I enroll?

Yes, but only during specific windows. You have a limited time to make changes to your coverage each year during the Annual Enrollment Period (October 15 to December 7). If you made a mistake during your Initial Enrollment Period, contact Medicare when ready to see if you can correct it before penalties take effect.