Home › Knowledge › Medicare Supplement (Medigap)
Vedanth Bhartee
Writer · Reviewed by Richard ChanUpdated Jun 12, 2026
10 min read
Medigap policies work alongside Original Medicare to help cover out-of-pocket costs like copayments and deductibles, allowing you to see any doctor nationwide who accepts Medicare.
Medicare Advantage plans replace Original Medicare by bundling Part A, Part B, and often Part D into a single plan that typically requires beneficiaries to use a specific network of doctors and hospitals.
You cannot have both a Medicare Supplement (Medigap) plan and a Medicare Advantage plan at the same time; it is illegal for an insurer to sell you a Medigap policy if you are enrolled in Medicare Advantage.
Navigating the choice between Medicare Supplement (known commonly as Medigap) and Medicare Advantage can feel overwhelming and deeply confusing. Both options are offered by private insurance companies, and some companies even provide both types of plans, which only adds to the complexity.
However, these plans function quite differently when it comes to how they provide coverage for your vital healthcare costs. It's absolutely crucial to grasp the distinction between Medigap and Medicare Advantage so you can make a confident, informed decision about your healthcare coverage and protect your retirement savings.
Medigap, a common short-hand for Medicare Supplement, is an insurance policy designed specifically to fill the "gaps" (in other words, the out-of-pocket costs you owe) under Original Medicare (Part A and Part B) coverage.
While Original Medicare is the standard default option provided directly by the government, it doesn't cover all of your healthcare costs. This can unexpectedly leave beneficiaries responsible for steep out-of-pocket expenses like deductibles, copays, and coinsurance. These are the exact "gaps" that a Medigap plan is designed to step in and cover.
By purchasing a Medigap plan, these stressful out-of-pocket costs are effectively "shifted" to the Medigap insurance company, who will cover the costs on your behalf.
Medigap plans provide much-needed predictability in your healthcare expenses in exchange for a consistent, reliable monthly premium that you pay.
In total, there are 10 standardized Medicare Supplement plans available in most states: Plans A, B, C, D, F, G, K, L, M, and N. All of these policies offer the same essential basic benefits, but some offer robust additional benefits, giving you the power to choose which one best meets your medical and financial needs.
Each "plan type" provides a different level of coverage which is strictly standardized and determined by the government. For Medicare-covered services, once Original Medicare has paid its share of your claims, it will automatically forward them to your Medigap plan to handle the rest.
Note: In Massachusetts, Minnesota, and Wisconsin, Medicare Supplement policies are standardized in a different way.
It is important to remember that Medigap plans do not include Part D (prescription drugs) coverage. You must proactively purchase a standalone Prescription Drug Plan (PDP) if you want dedicated drug coverage to afford your medications.
Medigap plans offer incredible financial predictability and give policyholders genuine peace of mind. In addition, beneficiaries have the empowering freedom to select doctors and specialists without frustrating network restrictions, as these plans work with all doctors nationwide that accept Medicare. Some Medigap plans even offer coverage for emergency medical care during international travel.
Once you firmly decide you want a Medigap plan alongside Original Medicare, you'll need to enroll. The best window for purchasing Medigap starts during the six-month period when you first sign up for Medicare Part B. This critical timeframe, known as the Medigap Open Enrollment Period, legally ensures that insurance companies must offer you a Medigap plan at the exact same price available to everyone else, regardless of your health status.
Once this enrollment period ends, obtaining a policy might become far more challenging. You may be forced to undergo medical underwriting, which could lead to higher monthly costs or even flat-out denial of coverage, particularly if your health is not currently optimal. (Compassionate exceptions to this rule exist in Connecticut, Massachusetts, Maine, and New York, where guaranteed issue protections are firmly in place.)
Considering whether a Medigap plan strictly suits your needs is crucial during your initial eligibility period. Waiting might result in permanently higher expenses or the heartbreaking inability to secure a plan later on. Therefore, it's vital to weigh your options carefully and make an informed, forward-looking choice about Medigap coverage when the opportunity first arises.
Medicare Advantage (also commonly known as "Part C" coverage) plans work very differently from Medicare Supplement plans. Instead of helping to pay for the lingering costs under Original Medicare, Medicare Advantage plans are designed to be a convenient, bundled "all-in-one" alternative to Original Medicare.
Medicare Advantage plans are required by law to provide the exact same baseline coverage for services covered under Original Medicare (Part A and B). However, they often generously bundle in coverage that is not included with Original Medicare, such as Part D (prescription drugs) coverage, as well as additional benefits like coverage for dental, vision, and hearing.
When you enroll in a Medicare Advantage plan, you are actively choosing to receive your Medicare coverage through the private plan provider rather than directly from the federal government.
Similar to the structured insurance that you may have received previously through an employer, Medicare Advantage plans are managed care plans. Often, you will have to receive your care from doctors, hospitals, and other providers strictly within the plan's specific network. The most common types of these plans are HMO and PPO plans.
Medicare Advantage will also still have deductibles, copays, and coinsurance obligations. However, unlike Original Medicare, they mercifully feature an annual out-of-pocket limit. That means that once you have paid out-of-pocket costs that add up to the plan's maximum annual limit, the plan will step in and pay 100% of your medical bills for the remainder of the calendar year.
While you may have to pay a monthly premium for your Medicare Advantage plan, many Medicare Advantage options are "$0 premium" plans, meaning there is no additional premium charged on top of your standard Part B premium.
Choosing a Medicare Advantage plan over Original Medicare can be highly advantageous for several reasons. Medicare Advantage plans elegantly consolidate hospital insurance, medical insurance, and often prescription drug coverage into a comprehensive package, offering the sheer convenience of all-in-one coverage. Additionally, these plans frequently provide extra benefits like dental, vision, hearing, and fitness programs, significantly enhancing your overall healthcare experience.
With a firm cost cap due to out-of-pocket maximums, Medicare Advantage plans can also offer strong financial security relative to Original Medicare by itself, which completely lacks annual spending limits.
Managed by private insurance companies, Medicare Advantage plans often feature structured care coordination, making them highly suitable for individuals seeking a more actively managed healthcare approach.
Furthermore, Medicare Advantage plans can offer immediate financial savings, as they often come with lower monthly premiums compared to certain Medigap plans. Carefully assessing your healthcare needs and preferences, budget constraints, and the benefits offered by different plans will reliably help you determine if a Medicare Advantage plan aligns with your requirements and provides comprehensive coverage tailored to your unique health situation.
People eligible for Medicare can smoothly enroll in Medicare Advantage during their initial enrollment period, typically encompassing their 65th birthday month, along with the three months before and after. Changing plans is also allowed during the annual Medicare open enrollment period, which runs from October 15 to December 7 each year, or during the Medicare Advantage open enrollment period from January 1 to March 31 annually.
Additionally, individuals may qualify for a special enrollment period, enabling necessary plan changes if they have moved out of their plan's service area or transitioned into a skilled nursing facility.
In terms of total enrollments across the country, 25% of Medicare beneficiaries (around 15 million people) are enrolled in Medigap plans, while 48% (around 28 million) are enrolled in Medicare Advantage. The user-friendly, bundled nature of Medicare Advantage plans has seen them gain immense popularity.
But how does Medicare Supplement truly differ from Medicare Advantage? The core differences between the two often boil down to the following:
With Original Medicare (including if you buy a Medigap plan) you can use any doctor across the entire country that accepts Medicare, while with Medicare Advantage you may only be able to see a plan's specific "in-network" doctors (some plans, such as PPO plans, will cover out-of-network doctors but at a noticeably higher cost).
Original Medicare has no cap on out-of-pocket costs. If smartly bundled with a Medigap plan, it can result in very comprehensive coverage, as the Medigap plan helps eliminate most of your out-of-pocket expenses (copays and coinsurances) in return for an additional monthly premium.
Medicare Advantage, on the other hand, typically has an $0 additional premium and an annual maximum limit on out-of-pocket costs that can range from $2,000 to $11,000, meaning you may face more variability in your monthly costs if your health declines.
Here's a helpful table that clearly summarizes the differences between the two:
| Medicare Supplement (with Original Medicare) | Medicare Advantage | |
| Description | Helps pay for all or most out-of-pocket costs for Medicare-covered services. | Bundled "all-in-one" alternative to Original Medicare that provides coverage in place of Original Medicare. |
| Premium | Premiums typically range from $100 to $300 a month, and may vary with your age and/or health status. | Premiums can range between $0 to more than $100 per month, however, the majority of Medicare Advantage enrollees pay $0. All enrollees in a plan pay the exact same regardless of age or health status. |
| Out-of-Pocket Costs | Limited to no out-of-pocket costs for covered services. Plans cover out-of-pocket costs in return for you paying the reliable monthly premium. | In 2026, out-of-pocket costs are capped at a maximum of $9,200 a year for in-network services and $12,450 for out-of-network services. Many costs are charged on a copay (fixed dollar) basis so you know what costs are upfront. |
| Doctors and Hospitals | As Medicare Supplement plans work with Original Medicare, you can safely see any doctor that participates in Medicare. | HMOs: In-network providers only. PPOs: Any provider, but out-of-network providers cost significantly more. |
| Part D Prescription Drug Coverage | Not included. You must deliberately buy a separate standalone Prescription Drug Plan (PDP). | Most plans conveniently bundle in Part D coverage. |
| Additional benefits (e.g., vision, dental and hearing) | Not covered. | Included with most Medicare Advantage plans. |
Deciding between Medigap and Medicare Advantage ultimately involves deeply understanding your specific coverage needs and financial boundaries.
Medigap plans serve as powerful supplements to Original Medicare, smoothly filling the expensive gaps in Parts A and B, and providing comprehensive nationwide coverage. However, they cannot be used in conjunction with Medicare Advantage.
Medicare Advantage plans provide an all-in-one alternative to Original Medicare, fully encompassing the same core coverage as Parts A and B, often with highly desired additional benefits like prescription drug coverage (Part D), dental, vision, and hearing care. Medicare Advantage plans can be more economical and budget-friendly if you don't use a lot of health services day-to-day.
It's absolutely crucial to aggressively assess not only your current healthcare needs but also realistically anticipate your future medical requirements. Consider factors such as your tight budget, preferred healthcare providers, regular prescription medications, and any chronic conditions you may be facing. As Medigap plans work with Original Medicare, they offer the unbeatable flexibility of choosing doctors and specialists without network restrictions, providing total peace of mind and financial predictability.
In stark contrast, Medicare Advantage plans often have strict networks and may require formal referrals for specialists. Additionally, realistically think about whether you travel frequently and might suddenly need coverage outside your local area. Carefully evaluating these aspects will empower you to make a well-informed decision that guarantees your healthcare coverage meets your needs comprehensively and effectively.