Medicare is our country’s health insurance program for people age 65 or older. Certain people younger than age 65 can qualify for Medicare too, including those with disabilities and those who have permanent kidney failure.
The program helps with the cost of health care, but it does not cover all medical expenses or the cost of most long-term care. You have choices for how you get Medicare coverage. If you choose to have Original Medicare (Part A and Part B) coverage, you can buy a Medicare Supplement Insurance (Medigap) policy from a private insurance company.
The Parts of Medicare
Social Security enrolls you in Original Medicare (Part A and Part B).
- Medicare Part A (hospital insurance) helps pay for inpatient care in a hospital or limited time at a skilled nursing facility (following a hospital stay). Part A also pays for some home health care and hospice care.
- Medicare Part B (medical insurance) helps pay for services from doctors and other health care providers, outpatient care, home health care, durable medical equipment, and some preventive services.
Other parts of Medicare are run by private insurance companies that follow rules set by Medicare.
- Supplemental (Medigap) policies help pay Medicare out-of-pocket copayments, coinsurance, and deductible expenses.
- Medicare Advantage Plan (previously known as Part C) includes all benefits and services covered under Part A and Part B — prescription drugs and additional benefits such as vision, hearing, and dental — bundled together in one plan.
- Medicare Part D (Medicare prescription drug coverage) helps cover the cost of prescription drugs.
Most people age 65 or older are eligible for free Medical hospital insurance (Part A) if they have worked and paid Medicare taxes long enough. You can enroll in Medicare medical insurance (Part B) by paying a monthly premium. Some beneficiaries with higher incomes will pay a higher monthly Part B premium. To learn more, read Medicare Premiums: Rules For Higher-Income Beneficiaries.
Should I Sign Up For Medical Insurance (Part B)?
With our online application, you can sign up for Medicare Part A (hospital insurance) and Part B (medical insurance). Because you must pay a premium for Part B coverage, you can turn it down.
If you’re eligible at age 65, your initial enrollment period begins three months before your 65th birthday, includes the month you turn age 65, and ends three months after that birthday.
If you choose not to enroll in Medicare Part B and then decide to do so later, your coverage could be delayed and you may have to pay a higher monthly premium for as long as you have Part B. Your monthly premium will go up 10 percent for each 12-month period you were eligible for Part B, but didn’t sign up for it, unless you qualify for a “Special Enrollment Period” (SEP).
If you don’t enroll in Medicare Part B during your initial enrollment period, you have another chance each year to sign up during a “general enrollment period” from January 1 through March 31. Your coverage begins on July 1 of the year you enroll. Read our Medicare publication for more information.If you have a Health Savings Account (HSA) or health insurance based on current employment, you may want to ask your personnel office or insurance company how signing up for Medicare will affect you.
Special Enrollment Period (SEP)
If you have medical insurance coverage under a group health plan based on your or your spouse’s current employment, you may not need to apply for Medicare Part B at age 65. You may qualify for a “Special Enrollment Period” (SEP) that will let you sign up for Part B during:
- Any month you remain covered under the group health plan and you or your spouse’s employment continues.
- The 8-month period that begins with the month after your group health plan coverage or the employment it is based on ends, whichever comes first.
How To Apply Online For Just Medicare
If you are within three months of turning age 65 or older and not ready to start your monthly Social Security benefits yet, you can use our online retirement application to sign up just for Medicare and wait to apply for your retirement or spouses benefits later. It takes less than 10 minutes, and there are no forms to sign and usually no documentation is required.
To find out what documents and information you need to apply, go to the Checklist For The Online Medicare, Retirement, and Spouses Application.
To help protect your identity, your Medicare card has a Medicare number that’s unique to you. If you did not receive your red, white, and blue Medicare card, there may be something that needs to be corrected, like your mailing address. You can update your mailing address by signing in to or creating your personal my Social Security account. Learn more about your Medicare card.
Already Enrolled in Medicare
If you have Medicare, you can get information and services online. Find out how to manage your benefits.
If you are enrolled in Medicare Part A and you want to enroll in Part B, please complete form CMS-40B, Application for Enrollment in Medicare – Part B (medical insurance). If you are applying for Medicare Part B due to a loss of employment or group health coverage, you will also need to complete form CMS-L564, Request for Employment Information.
You can use one of the following options to submit your enrollment request under the Special Enrollment Period:
- Go to “Apply Online for Medicare Part B During a Special Enrollment Period” and complete CMS-40B and CMS-L564. Then upload your evidence of Group Health Plan or Large Group Health Plan.
- Fax or mail your CMS-40B, CMS-L564, and secondary evidence to your local Social Security office (see list of secondary evidence below).
- State “I want Part B coverage to begin (MM/YY)” in the remarks section of the CMS-40B form or online application.
- If possible, your employer should complete Section B.
- If your employer is unable to complete Section B, please complete that portion as best as you can on behalf of your employer without your employer’s signature and submit one of the following forms of secondary evidence:
- Income tax form that shows health insurance premiums paid.
- W-2s reflecting pre-tax medical contributions.
- Pay stubs that reflect health insurance premium deductions.
- Health insurance cards with a policy effective date.
- Explanations of benefits paid by the GHP or LGHP.
- Statements or receipts that reflect payment of health insurance premiums.
You’ll have Original Medicare (Part A and Part B) unless you make another choice. You can decide to add a drug plan (Part D) or buy a Medigap policy to help pay for costs that Original Medicare doesn’t cover. You can choose to join a Medicare Advantage Plan (Part C) and get all your Medicare coverage (including drugs and extra benefits like vision, hearing, dental, and more) bundled together in one plan.
What Happens After I Apply?
The Centers for Medicare & Medicaid Services (CMS) manages Medicare. After you are enrolled, they will send you a Welcome to Medicare packet in the mail with your Medicare card. You will also receive the Medicare & You handbook, with important information about your Medicare coverage choices.
Other Medicare Enrollment Options
If you live in Puerto Rico you will not receive Medicare Part B (medical insurance) automatically. You will need to sign up for it during your initial enrollment period, or you will pay a penalty. To sign up, please call our toll-free number at 1-800-772-1213 (TTY 1-800-325-0778). You also may contact your local Social Security office. You can find your local Social Security office by using our Office Locator.If you do not live in the U.S. or one of its territories you can also contact the Federal Benefits Unit that provides service to your country of residence.