Your Guide To Original Medicare Eligibility And Enrollment

Everything You Need To Know About Medicare Eligibility And The Medicare Enrollment Process

Eligibility For Medicare

The following contains information about Original Medicare eligibility (Medicare Part A & Medicare Part B).

Who Qualifies for Medicare?

Original Medicare is available to the following individuals:

  • Age 65 or older
  • Under 65 and:
    • Disabled and receiving Social Security  disability payments for at least 24 months
    • Diagnosed with End-Stage Renal Disease (ESRD) or Amyotrophic Lateral Sclerosis (ALS)

In addition, individuals must be a U.S. citizen or permanent resident who has lived in the U.S. for five consecutive years before applying for Medicare.

Medicare Work History

Qualification for Medicare Part A is tied to an individual’s working history under Social Security or the Railroad Retirement Board (“RRB”).

For individuals 65 or older, the individual (or their spouse) must have worked for ten or more years and paid into Medicare through payroll (FICA) taxes. Government employees not subject to FICA must have paid Medicare payroll taxes.

Qualifying for Medicare through a disability is also dependent on work credits. The work credits vary based on the individual’s age and the age they were disabled.

Individuals who meet the work history requirement are eligible for Medicare Part A (hospital insurance) without paying any monthly premium. This is known as “premium-free” Part A. Spouses can qualify for premium-free Part A on their spouse’s work record. Spouses can also qualify through a deceased or divorced spouse.

If an individual’s work history is insufficient, they can purchase Medicare Part A. But they must pay monthly premiums. Premiums are tiered based on the number of work credits.

No work credits are required for Medicare Part B, but most Part B requires monthly premiums (regardless if you get premium-free Part A).

Medicare Enrollment Timing

The are four ways to enroll in Original Medicare once you become eligible. Some individuals are automatically enrolled. Others must actively sign up during one of three standard enrollment periods:

  •  Initial Enrollment Period (IEP)
  • General Enrollment Period (GEP)
  • Special Enrollment Period (SEP)

#1 - Automatic Medicare Enrollment

Turning 65

Individuals who are turning 65, AND have already been collecting Social Security (or RRB) retirement benefits for at least four months, will be automatically enrolled in Original Medicare.

If you are automatically enrolled, you will get a notification in the mail two to three months before your 65th birthday. You’ll also receive a Medicare “Welcome Packet” and your Medicare card. 

If you are automatically enrolled in Medicare, you can elect to opt-out if you wish. Medicare will provide documentation explaining how to opt out of Medicare Part B. However, you must cease receiving Social Security benefits to opt out of Medicare Part A. (Plus, return all retirement benefits you’ve previously received.)


Individuals who are permanently disabled will be automatically enrolled in Original Medicare after their 24th Social Security (or RRB) disability payment.

Individuals diagnosed with ALS will be automatically enrolled in Medicare when their disability begins. 

Those with ESRD become eligible one to three months before dialysis or transplant. Enrollment will also be automatic.

#2 - Initial Enrollment Period (IEP)

Individuals turning 65 can first sign up for Medicare during a 7-month period surrounding their 65th birthday. This period begins three months before the month they turn 65, includes the month they turn 65, and ends three months after the month they turn 65. This is known as the Initial Enrollment Period, commonly called “IEP.”

If an individual enrolls during the first three months of their IEP coverage will begin the first day of their birthday month. The one exception is if somebody is born on the first day of a month, their Medicare coverage will begin on the first day of the prior month.

If an individual waits to enroll until their birthday month, or one of the three months following their birthday month, Medicare Part B coverage will start the first day of the month after they sign up. In most cases, if you qualify for premium-free Part A, Part A coverage will retroactively start the first day of your birthday month.

#3 - general Enrollment Period (GEP)

Individuals that don’t sign up for Medicare during their Initial Enrollment Period must wait until the General Enrollment Period to enroll. (Unless they qualify for a Special Enrollment Period as described below.)

The General Enrollment Period occurs between January 1st and March 31st of every year. Coverage will begin the first day of the month following the month you enroll.

If you are eligible for premium-free Part A, you are not confined to the GEP. You can enroll in premium-free Part A anytime. In that case, the GEP would only apply to Medicare Part B.

If somebody misses the IEP and waits until the GEP, they may incur late-enrollment penalties if they do not have other qualifying health coverage.

#4 - Special Enrollment Period (SEP)

The Special Enrollment Period is for individuals who didn’t sign up during their IEP and have specific “qualifying” circumstances.

The most common SEP is for individuals who continued working past age 65 and were covered by an employer-provided group health plan. These individuals can enroll in Medicare any time while working and up to eight months after they stop working. This eight-month period begins the month after either employment or employment-based coverage ended – whichever occurred first. If this SEP is missed, the individual must wait until the next GEP.

Medicare coverage will become effective the first month following enrollment. To avoid a gap in health coverage, workers should sign up for Medicare the month before their group coverage ends.

COBRA coverage, retiree health plans, VA coverage, and individual health insurance are not considered coverage based on current employment. Therefore, a SEP will not apply, and late-enrollment penalties may occur. 

Sign Up For Medicare

You will sign up for Medicare Parts A and B through the Social Security Administration. The are three ways to do so:

  • Online
  • Phone Call
  • Local Social Security Office

Enrolling in Medicare Online

Enrolling in Medicare through the Social Security Administration’s website is likely the quickest way to enroll. You can go to, and the website will walk you through the steps. 

On the website, you can enroll in Part A only, Part B only, or both Parts A and B together.

Note: If you qualify for premium-free Part A through your spouse’s work record, you will not be able to sign up online.  

Other Ways To Enroll In Medicare

You can sign up for Medicare Parts A and B by calling the Social Security Administration’s national phone number at 1-800-772-1213. Just tell the representative you want to sign up for Medicare Parts A and/or B.

The number is available in most U.S. time zones Monday – Friday, 8:00 am to 7:00 pm. Call TTY 1-800-325-0778 if you are deaf or hard of hearing.

Note: It is normal to experience long wait times when calling Social Security.

Lastly, you can enroll by visiting your local Social Security office. If you don’t know where you’re local Social Security office is located, you can find it using this link:

Note: It appears that Social Security is pushing people to do everything online. Also, I recommend calling ahead to ensure the office takes local appointments that day.

What You'll Need To Enroll

You may need the following pieces of information to sign up:

  • Social Security number
  • Information about where you were born
  • Current health insurance information
  • Valid email address
  • Your existing Medicare number (if you already have Part A and are enrolling in Part B)

After You Enroll

After you enroll in Medicare, you can check the status of your enrollment online here:

You will be required to sign into your online account or create an account if you don’t have one. 

After you enroll in Medicare (and are accepted), you will receive your “Welcome Packet” and Medicare card in the mail within about three weeks.

Your Medicare card will contain your Medicare Beneficiary Identifier (MBI). You can also look this number up online. You’ll need this number to enroll in additional Medicare coverage, such as a Medicare Advantage Plan (Part C), a prescription drug plan (Part D), and/or a Medicare Supplement Plan (“Medigap”). 

If you have any questions about this, please don’t hesitate to contact us.

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