Medicare Supplement insurance, explained simply
Medicare Supplement Insurance, also called Medigap, is private insurance designed to work alongside Original Medicare. Original Medicare includes Part A for hospital insurance and Part B for medical insurance. After Medicare pays its share of the Medicare-approved amount for a covered service, a Medigap policy may pay some or all of your remaining share, depending on the plan you choose.
That remaining share can include certain deductibles, coinsurance, and copayments. Medigap is an additional policy, not a replacement for Original Medicare. In most cases, you need both Part A and Part B before you can buy it. Our Medicare insurance page explains the options we can help you compare.
How do Medicare and Medigap pay a claim?
Suppose you receive a service covered by Original Medicare. Medicare processes the claim first and pays its share of the Medicare-approved amount. Your Medigap insurer then pays the portion your particular plan covers. You are responsible for any amount still due under that plan. Many claims are passed from Medicare to the Medigap insurer automatically, although the process can vary.
Medigap generally helps with your share of Original Medicare-covered care; it does not turn a service that Medicare excludes into a covered service. Some plans also offer limited benefits for foreign travel emergencies, subject to their terms. Always compare the actual plan benefits instead of assuming every lettered plan pays the same remaining costs.
What does a Medicare Supplement plan cover?
Medigap policies are standardized in most states and identified by plan letters, such as Plan G or Plan N. Each policy with the same letter provides the same basic benefits regardless of the insurance company selling it, but premiums can differ. Different plan letters cover different combinations of Medicare cost sharing, so the lowest premium may not mean the lowest total cost for you. Not every lettered plan is available everywhere.
When comparing Medicare Supplement plans, look at your expected use of care, the benefits in each letter, the monthly premium, how the insurer prices policies over time, and what you could pay when you use services. Medicare's official comparison chart shows the benefits by plan letter. Rules for standardization differ in Massachusetts, Minnesota, and Wisconsin; Sonon Insurance does not list those states among its service area.
What does Medigap not cover?
Medigap plans generally do not cover routine dental or vision care, hearing aids, glasses, long-term custodial care, or private-duty nursing. Policies sold after 2005 also do not include outpatient prescription drug coverage. If you want drug coverage while using Original Medicare with Medigap, you can consider a separate Medicare Part D plan.
You pay the Medigap insurer a separate monthly premium in addition to any Part B premium and any premium for a Part D plan you choose. Medigap is not the same as a Medicare Advantage plan. Medicare Advantage is another way to receive Medicare benefits, while Medigap supplements Original Medicare. A Medigap policy cannot pay a Medicare Advantage plan's copayments, deductibles, or premiums. Insurers generally cannot sell you a Medigap policy while you are in Medicare Advantage unless you are switching back to Original Medicare.
When can you enroll in Medigap?
For many people, the best time to buy is the one-time, six-month Medigap Open Enrollment Period. It begins on the first day of the month you are both 65 or older and enrolled in Medicare Part B. During that period, you generally have the right to buy any Medigap policy sold in your state without being denied or charged more because of health problems. The timing is different from Medicare's yearly fall Open Enrollment Period for Medicare Advantage and Part D. The fall period does not, by itself, guarantee you can buy or switch Medigap policies.
After your Medigap Open Enrollment Period, an insurer may use medical underwriting unless you qualify for a guaranteed issue right or your state gives you additional protection. Certain losses of coverage or moves can create special rights, but the details and deadlines matter. Federal rules do not require insurers to offer Medigap to people under 65; some states provide additional access. Check your specific state and situation before dropping existing coverage or making a change.
How to decide whether Medigap fits your needs
Start with how you prefer to receive care and how much predictability you want in your out-of-pocket costs. Compare Original Medicare with a Medicare Supplement and, if needed, a separate Part D plan against the Medicare Advantage options available where you live. Review premiums, benefits, doctor participation, prescription coverage, travel needs, and the rules for changing coverage later. The right combination depends on your health needs, finances, and eligibility.
Sonon Insurance can help you understand Medicare Supplement options and compare available plans in Pennsylvania, New Jersey, Delaware, Maryland, Virginia, Illinois, Georgia, Florida, and Colorado. Availability and enrollment rights vary by state, insurer, and individual circumstances. If you are approaching Part B enrollment or considering a switch, review the timing before you act.
Frequently asked questions
Is Medicare Supplement insurance the same as Medigap?
Yes. Medigap is another name for Medicare Supplement Insurance, a private policy that helps pay some of your out-of-pocket share under Original Medicare.
Do I still need Medicare Part B with a Medigap plan?
Yes. Medigap works with Original Medicare, and you generally need both Part A and Part B to buy a policy. You continue paying applicable Medicare premiums as well as the Medigap premium.
Does Medigap include prescription drugs?
New Medigap policies sold after 2005 do not include prescription drug coverage. You can consider a separate Medicare Part D plan if you want outpatient drug coverage.
Can I switch Medigap plans every fall without health questions?
The yearly fall Medicare Open Enrollment Period does not automatically give you a federal right to switch Medigap plans. Outside your one-time Medigap Open Enrollment Period, underwriting may apply unless you have a guaranteed issue right or additional state protection.
Helpful resources
Coverage, eligibility, and plan terms vary by carrier and state. This article is general information, not a promise of coverage or individualized financial advice.
