How to Enroll in Medicare: A Step-by-Step Guide

Most people enroll in Medicare during their seven-month Initial Enrollment Period, which starts three months before the month they turn 65 and ends three months after. You can sign up online at SSA.gov, by phone, or at a local Social Security office. There is no fee to apply.

Medicare enrollment runs on a fixed set of dates, and those dates depend on your birthday, your work history, and whether you have coverage through a current job. This guide explains when to sign up and how to submit the application. It also covers which documents to have ready, what happens if you enroll after your period closes, and how the rules change for people who keep working past 65.

Solace advocates are healthcare professionals, including nurses, social workers, and clinical researchers, who have worked inside the healthcare system. An advocate can confirm your specific enrollment dates, help you assemble your paperwork, and follow up with Social Security until your coverage is active.

When can I enroll in Medicare?

Most people can enroll during their Initial Enrollment Period (IEP), a seven-month period that starts three months before the month you turn 65, includes your birthday month, and continues for three months after. If your birthday falls on the first of the month, the entire period shifts one month earlier, and coverage can start the month before you turn 65.

Timing within the IEP affects your start date. If you sign up during the three months before your birthday month, coverage begins on the first day of your birthday month. If you sign up during your birthday month or the three months after, coverage begins on the first day of the month after you apply, according to the Social Security Administration (SSA).

If you already receive Social Security or Railroad Retirement benefits at least four months before you turn 65, Medicare enrolls you in Part A and Part B automatically, and coverage begins on the first day of your birthday month. If you have not started Social Security benefits yet, you need to sign up for Medicare yourself.

What happens if I miss my enrollment window?

If you enroll after your Initial Enrollment Period ends and you do not qualify for a Special Enrollment Period, Medicare adds a late enrollment penalty to your monthly premium. The penalty stays in place for as long as you have that coverage.

The penalty is calculated differently for each part of Medicare.

• Part B: Medicare adds 10% of the standard Part B premium to your monthly bill for each full 12-month period you were eligible but did not enroll. The increase is permanent.
• Part D: Medicare adds 1% of the national base beneficiary premium ($38.99 in 2026, per CMS) for each full month you went without creditable drug coverage. The penalty applies once you have gone 63 or more days without that coverage, and it lasts for as long as you have Part D.
• Part A: A penalty applies only if you have to pay a premium for Part A. Most people do not.

There are two ways to enroll after your Initial Enrollment Period closes.

General Enrollment Period. This runs January 1 through March 31 each year. You can sign up for Part A and Part B, and coverage starts on the first day of the month after you apply. Late enrollment penalties may still apply.

Special Enrollment Period. This is available after certain life events, such as losing coverage through a job. If you qualify, you can enroll outside the standard dates without a penalty.

How do I sign up for Medicare Part A and Part B?

The Social Security Administration (SSA) handles all enrollment for Medicare Part A and Part B. You can apply online, by phone, or in person, and there is no fee to apply.

Online: Go to SSA.gov. The application typically takes 10 to 30 minutes, and you can save your progress and finish later.

By phone: Call 1-800-772-1213 (TTY 1-800-325-0778), Monday through Friday, 8 a.m. to 7 p.m. local time.

In person: Schedule an appointment at your local Social Security office.

After you submit your application, SSA reviews it and mails your Medicare card, usually within a few weeks. You can check the status of your application through a my Social Security account.

The cost of Part A and Part B

Most people pay no premium for Part A because they or a spouse paid Medicare taxes for at least 10 years (40 work quarters).

Part B has a monthly premium; in 2026, the standard premium is $202.90 and the standard annual deductible is $283. People with higher incomes pay more, based on their tax return from two years prior. If you already receive Social Security benefits, the Part B premium comes out of your monthly payment.

Solace advocates work with these applications regularly. An advocate can confirm your exact enrollment dates, review your application before you submit it, and follow up with SSA if processing takes longer than expected.

What documents do I need to enroll in Medicare?

You need your Social Security number, proof of your age and U.S. citizenship or lawful residency, and details about any health coverage you have through an employer. SSA says it usually requires no documents for the online application and will contact you if it needs more.

Have these ready before you start:

• Your Social Security number
• Your date and place of birth
• Proof of U.S. citizenship or lawful residency, if SSA requests it
• The start and end dates of any employer health coverage for you or your spouse

If you delayed Part B because of employer coverage. SSA requires two additional forms when you enroll:

• CMS-40B (Application for Enrollment in Medicare Part B)
• CMS-L564 (Request for Employment Information), which your employer completes in part to confirm the dates of your group health coverage

If your employer cannot complete the L564, SSA accepts other proof of coverage, such as W-2s or pay stubs that show health insurance deductions.

You can start the online application before every document is in hand, since the form saves your progress. Having your Social Security number and any employer coverage dates ready before you begin reduces the chance of a processing delay.

How do I enroll in Medicare Advantage, Part D, or Medigap?

Signing up for Part A and Part B through SSA gives you hospital and medical insurance only. Prescription drug coverage, Medicare Advantage, and Medigap are separate enrollments you complete with private insurers once your Original Medicare is active.

Once you have your Medicare number, you can add one or more of the following:

• Part D is a standalone prescription drug plan that works alongside Original Medicare.
• Medicare Advantage (Part C) is a private plan that combines Parts A and B, and usually Part D, under one insurer. It replaces Original Medicare as the way you receive your benefits.
• Medigap is a supplemental policy that helps pay the deductibles and coinsurance Original Medicare leaves you responsible for. It works with Original Medicare only, so you cannot pair it with a Medicare Advantage plan.

When to enroll in Medicare Advantage or Part D

Both have their own enrollment timelines tied to your Initial Enrollment Period. If you want to change plans later, you can switch during the **Annual Enrollment Period: October 15 through December 7.**

When to enroll in Medigap

Your Medigap Open Enrollment Period is the six-month period that begins the first month you are both 65 or older and enrolled in Part B. During those six months, insurers must sell you any Medigap policy they offer, regardless of your health history. After it closes, insurers in most states can decline your application or charge more based on your health history.

Should I enroll in Medicare if I'm still working?

If you are still working at 65 and have group health coverage through your own or your spouse's current employer, you can usually delay Part B without a penalty. Whether you should delay is primarily dependent on how many employees the company has.

Employer with 20 or more employees: Your employer plan pays first and Medicare pays second. Many people in this situation enroll in premium-free Part A at 65 and delay Part B until the job or the coverage ends. When that happens, an eight-month Special Enrollment Period opens for Part B, and coverage starts the month after SSA receives your forms. You then have two months to join a Medicare Advantage or Part D plan.

Employer with fewer than 20 employees: Medicare generally becomes the primary payer at 65. If you delay Part B, your employer plan may pay only the share it would owe after Medicare, leaving you responsible for the rest. Most people in this situation enroll in both Part A and Part B during their Initial Enrollment Period.

Two additional factors to consider:

• COBRA and retiree coverage do not count as current employer coverage. They do not let you delay Part B, and your eight-month Special Enrollment Period starts when your employment ends, not when COBRA ends.
• Enrolling in any part of Medicare ends your eligibility to contribute to a health savings account (HSA). If you plan to keep contributing, you may want to delay Part A as well, which means delaying Social Security benefits too.

These rules depend on your employer's size and plan terms. Confirm your situation with your benefits administrator, SSA, or your State Health Insurance Assistance Program (SHIP) before deciding to delay.

Medicare enrollment periods at a glance

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Get Help With Your Medicare Enrollment

Medicare enrollment comes down to three questions: when your period opens, which parts you need now, and whether employer coverage changes your timeline. The answers depend on details specific to your situation, and getting them right the first time avoids penalties that last for years.

A Solace advocate confirms your enrollment dates, helps you gather the required documents, and coordinates with Social Security until your coverage is active. If you are adding Part D, Medicare Advantage, or Medigap, your advocate helps you organize the deadlines and paperwork for each one.

Find a patient advocate and get your Medicare enrollment done correctly the first time.

Frequently Asked Questions

When should I enroll in Medicare?

Most people should enroll during their Initial Enrollment Period, the seven-month period that starts three months before the month they turn 65. Enrolling during this period prevents coverage gaps and the late enrollment penalties that apply to Part B and Part D. If you have group health coverage through your own or your spouse's current employer with 20 or more employees, you can usually delay Part B without a penalty until that coverage ends.

What happens if I miss my Medicare enrollment period?

If you miss your Initial Enrollment Period and do not qualify for a Special Enrollment Period, your next opportunity is the General Enrollment Period, January 1 through March 31 each year, with coverage starting the month after you apply. A late enrollment penalty of 10% for each full 12-month period you delayed is added to your Part B premium for as long as you have Part B. A separate penalty applies to Part D if you went 63 or more days without creditable drug coverage.

Do I need to enroll in Medicare if I'm still working?

It depends on the size of your employer. If you have coverage through a current employer with 20 or more employees, you can typically delay Part B without a penalty and enroll later during an eight-month Special Enrollment Period after that coverage ends. If your employer has fewer than 20 employees, Medicare generally becomes your primary insurance at 65, and most people in that situation enroll in Part A and Part B during their Initial Enrollment Period.

How much does Medicare Part B cost in 2026?

The standard monthly Part B premium is $202.90 in 2026, with an annual deductible of $283, according to the Centers for Medicare & Medicaid Services. People with higher incomes pay an income-related adjustment on top of the standard premium. Most people pay no monthly premium for Part A if they or a spouse paid Medicare taxes for at least 10 years.

Can I enroll in Medicare online?

Yes. You can apply for Medicare Part A and Part B online through the Social Security Administration at SSA.gov. The application typically takes 10 to 30 minutes, you can save your progress and finish later, and there is no fee to apply. Medicare Advantage, Part D, and Medigap enrollments are handled separately through private insurers or the Plan Finder at Medicare.gov.

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