The Core Difference: How Each Plan Works

Medicare Advantage (Part C) is an alternative way to receive your Medicare benefits. A private insurance company contracts with Medicare to cover your Part A (hospital) and Part B (medical) benefits, usually for a lower or zero monthly premium. In exchange, you use that company's network of doctors and hospitals, and you typically pay a copay or coinsurance when you see a provider.

Medicare Supplement (Medigap) is insurance you buy from a private company to cover the gaps in Original Medicare — the deductibles, copays, and coinsurance that Medicare Part A and Part B do not pay. You keep Original Medicare and add the supplement on top. You can see any doctor or hospital that accepts Medicare, anywhere in the country.

The practical difference: with Advantage, the insurance company controls your network and what you pay per visit. With Supplement, Medicare controls what is covered, and the supplement fills in what Medicare leaves behind.

Key Takeaways

  • Medicare Advantage usually costs less per month but requires you to use in-network providers and may have higher costs per doctor visit.
  • Medicare Supplement costs more per month but lets you see any Medicare-accepting doctor and typically has lower or no copays per visit.
  • Advantage plans often include dental, vision, and hearing coverage that Original Medicare does not; Supplement plans do not.
  • Switching between Advantage and Supplement outside of open enrollment periods can be difficult and may involve waiting periods or denial for pre-existing conditions.
  • Your choice depends on whether you value lower monthly costs and extra benefits (Advantage) or flexibility and predictable per-visit costs (Supplement).

Medicare Advantage: Lower Monthly Cost, Network Restrictions

Most Medicare Advantage plans charge zero monthly premium, though some charge $50 to $200 per month. The trade-off is that you must use doctors and hospitals in the plan's network, except in emergencies. If you see an out-of-network provider, you pay the full bill yourself or a much higher copay.

When you visit a doctor, you typically pay a copay — often $20 to $50 per visit — rather than the coinsurance percentage you would pay with Original Medicare. Some plans cap your out-of-pocket costs at $6,700 to $7,550 per year (the amount varies by plan and changes yearly), which can protect you if you have a serious illness. Once you hit that cap, the plan covers the rest of your care for that year.

Advantage plans often bundle in benefits Original Medicare does not cover: dental cleanings and fillings, vision exams and glasses, hearing aids, and fitness programs. If you use these services, the value can offset the higher per-visit costs. However, these benefits vary widely by plan and by region — a plan in one county may offer dental coverage while the same company's plan in the next county does not.

The catch: if you move out of your plan's service area, you lose coverage and must switch plans. If you travel frequently or spend winters in another state, this matters.

Medicare Supplement: Higher Monthly Cost, Maximum Flexibility

Medicare Supplement plans cost $100 to $300 per month on average, depending on your age, location, and the plan letter (A, B, D, G, K, L, M, or N — each covers a different set of gaps). Unlike Advantage, the monthly cost is predictable and does not change based on how much care you use.

With Supplement, you see any doctor or hospital in the United States that accepts Medicare. There are no networks, no referrals, and no prior authorization. You pay your Medicare deductible and coinsurance, and the supplement covers what Medicare does not — often leaving you with zero out-of-pocket cost per visit, depending on which plan letter you choose.

Plan G, the most popular choice, covers the Part B deductible ($240 in 2024, though this changes yearly), all coinsurance, and the cost of a second opinion before surgery. Plan N is cheaper but requires you to pay small copays ($20 per doctor visit, $50 per emergency room visit) and coinsurance for some services. Plan A is the least expensive but does not cover the Part B deductible.

Supplement plans do not include dental, vision, hearing, or fitness benefits. If you need these services, you pay out of pocket or buy separate coverage.

When Advantage Makes Sense

Choose Advantage if you want to minimize your monthly premium and you are comfortable using a specific network of doctors. This works well if you have a primary care doctor you like who is in-network, you do not travel much, and you use dental or vision services regularly (since Advantage often covers these).

Advantage is also a reasonable choice if you are healthy and do not expect frequent doctor visits. The lower monthly cost means you save money when ready, and the out-of-pocket cap protects you if something unexpected happens.

If you live in a rural area with limited providers, check whether Advantage plans are even available in your county. Some rural areas have only one or two options, or none at all.

When Supplement Makes Sense

Choose Supplement if you see multiple doctors, travel frequently, or want the certainty of knowing your costs in advance. This works well if you have established relationships with specialists who may not be in any single Advantage network, or if you move between states seasonally.

Supplement is also the better choice if you have a chronic condition that requires frequent visits. The higher monthly cost is offset by lower per-visit costs, and you avoid the hassle of checking whether each provider is in-network.

If you are willing to pay more per month for simplicity and choice, Supplement removes the guesswork from your healthcare decisions.

The Cost Comparison: What You Actually Pay

The total cost depends on how much healthcare you use. Here is how to think about it:

Low healthcare use: Advantage wins. You pay $0 to $200 per month and see a doctor twice a year at $20 to $50 per visit. Total: roughly $240 to $500 per year. With Supplement, you pay $1,200 to $3,600 per year in premiums alone, even if you see no one.

Moderate healthcare use: The costs converge. You might pay $2,000 to $4,000 per year with Advantage (premium plus copays) and $1,500 to $4,000 per year with Supplement (premium plus small copays). The winner depends on which doctors you see and whether they are in-network.

High healthcare use: Supplement often wins. Once you hit the Advantage out-of-pocket cap (usually $6,700 to $7,550), you stop paying per visit. But if you are paying $50 per visit with Advantage and see 20 specialists per year, you hit that cap quickly. With Supplement, you pay the monthly premium and little else per visit. Over a full year, Supplement may cost less.

The only way to know which is cheaper for you is to list your current doctors, check whether they are in-network for the Advantage plans available in your area, and calculate the total: monthly premium plus expected copays.

Switching Between Plans: Timing and Restrictions

You can switch from Advantage to Supplement or vice versa, but timing matters. During the Annual Enrollment Period (October 15 to December 7 each year), you can switch with no restrictions. Outside this window, your options are limited.

If you are switching from Advantage to Supplement, you have a one-time window: within 63 days of losing Advantage coverage (usually because you moved out of the service area). During this window, insurance companies cannot deny you or charge you more based on pre-existing conditions.

If you are switching from Supplement to Advantage, there is no special protection. You can switch during open enrollment, but outside that window, you may face waiting periods or denial if you have a pre-existing condition. Some states have protections, but not all.

The lesson: choose carefully the first time. Switching is possible but can be expensive or complicated if you wait too long.

Frequently Asked Questions

Can I have both Medicare Advantage and Medicare Supplement at the same time?

No. Medicare rules prohibit it. You choose one or the other. If you enroll in Advantage, your Supplement coverage ends. If you enroll in Supplement, your Advantage coverage ends.

What happens to my Advantage plan if I move to a different state?

Your coverage ends on the last day of the month you move. You must enroll in a new plan in your new state during the open enrollment period or within 60 days of losing coverage due to the move. If you miss this window, you may not be able to enroll until the next open enrollment period.

Do I have to use Original Medicare with a Supplement plan?

Yes. Supplement plans only work with Original Medicare (Part A and Part B). You cannot use a Supplement with Advantage. You also must have Part D (prescription drug coverage) separately if you want it.

Which Supplement plan letter should I choose?

Plan G covers the most gaps and is the most popular choice for new enrollees. Plan N is cheaper but requires small copays. Plan A is the least expensive but does not cover the Part B deductible. Compare the monthly cost of each plan available in your area and decide based on how much you expect to use healthcare.

Does Advantage cover prescription drugs?

Most Advantage plans include Part D (prescription drug coverage) bundled in. With Supplement, you must buy Part D separately. Check your plan documents to confirm what drugs are covered and at what cost.