Medicare is the federal health program for people who are 65 and older, certain younger people with disabilities, and people with End-Stage Renal Disease, sometimes called ESRD.

You are first eligible for Medicare typically at age 65. You have a 7-month Initial Enrollment Period to sign up for Part A and/or Part B. This begins 3 months before your 65th birthday month and ends 3 months after your birth month. Your coverage can start as early as the first day of the month you turn 65, unless your birthday is on the first day of the month. In that case, it can start the first of the month prior to turning 65. Individuals with disabilities can be eligible for Medicare earlier than age 65.

If you are covered by an employer health plan with more than 20 employees, generally you do not have to sign up for Medicare when you turn 65. If your employer has less than 20 employees, you should enroll in Medicare Part A & B when you are first eligible to avoid any late enrollment penalties. Companies with over 20 employees are considered the “Primary Payer” by Medicare, which means the company health plan will pay first. In this case, you can postpone enrolling in Medicare when first eligible and sign up later during a Special Enrollment Period. Some people opt to enroll in Part A only when they are first eligible, even if they have an employer plan that is considered Primary because Part A is typically premium free for most people. There are some situations where you may not want to do this, however, like if you or your employer contribute to a Health Savings Account (HSA).

You can enroll in Medicare Part A and/or Medicare Part B in the following ways:

1. Online at www.SocialSecurity.gov
2. By calling Social Security at 1-800-772-1213 (TTY users 1- 800-325-0778), Monday through Friday, from 7 AM to 7 PM
3. In person at your local Social Security office

You can be enrolled in both Medicare and an employer plan, but it might not be the best course of action for you. For companies with over 20 employees, the employer plan is the primary payer and Medicare is secondary. In this case, you are not required to enroll in Medicare when first eligible if you remain covered under the employer plan. When you leave the employer coverage, you’ll qualify for a Special Enrollment Period.

For companies under 20 employees, Medicare is the primary payer and the employer plan is secondary. In this case, you should sign up for Medicare when first eligible to avoid penalties later. Keep in mind that while you may be eligible for premium-free Part A (Hospital Insurance), you will have to pay a premium to have Medicare Part B.

Yes, as long as your employer has more than 20 employees. Many people who are still working and covered under an employer plan with more than 20 employees enroll in Part A but postpone enrolling in Part B. This is because Part B charges a monthly premium and often duplicates the employer plan coverage. If you are enrolled in Medicare and an employer plan, Medicare will coordinate benefits. If the company you work for has more than 20 employees, Medicare will pay out as a secondary payer and the company plan pays out as primary payer. It’s important to note that if you enroll in Medicare (Part A or Part A & B), you can no longer contribute to a health savings account (HSA).

If you are enrolled in Medicare Part A, you may no longer contribute into a health savings account (HSA). Your employer can no longer contribute to an HSA on your behalf either. If you are enrolled in an HSA compatible health plan through your employer and wish to keep contributing pretax dollars into your HSA, you should consider postponing enrollment into Part A.

It really depends on your specific situation. If you or your spouse are considering leaving your employer coverage and enrolling in Medicare, you’ll want to consider things like:

• How the premium costs compare. Consider what you pay in premium each month for your employer plan and what the Medicare package will cost.
• How your coverage and out-of-pocket costs compare. Consider how the employer plan benefits compare to the Medicare plan benefits as well as your out-of-pocket costs like deductibles, co-insurance, copays and annual maximums. 

Medicare has gaps in coverage and cost-sharing which is why most people add on a Medicare insurance plan. Medicare insurance plans are offered by private insurance companies, not Medicare. There are two different types of Medicare Health Insurance plans, and you pick one or the other:

1. Medicare Advantage plans (also known as Part C or MA). Note that these typically include Part D prescription drug coverage.
2. Medicare Supplement (also known as Medigap). Note that these plans do not include prescription drug coverage so to have that, you would need to enroll in a stand-alone Part D prescription drug plan. 

* You will continue to pay your Medicare Part B premium in addition to the premiums for the plan you select.