The core difference: how each plan works with Medicare

Medicare Advantage and Medicare Supplement are two different ways to get coverage beyond Original Medicare (Parts A and B). They work in opposite directions, and that shapes everything about cost, choice, and how you pay.

Medicare Advantage is an alternative to Original Medicare itself. You enroll in a private insurance plan — usually an HMO or PPO — that takes over your Part A and Part B coverage. The plan collects a monthly premium from you and a payment from Medicare. You use that plan's network of doctors and hospitals. Medicare Supplement, by contrast, works alongside Original Medicare. You keep your Medicare coverage and buy a separate policy from a private insurer to cover the gaps — the deductibles, copays, and coinsurance that Original Medicare leaves you responsible for.

Neither is objectively "better." The right choice depends on your health, how much you travel, which doctors you see, and how much predictability you want in your out-of-pocket costs.

Key Takeaways

  • Medicare Advantage limits you to in-network doctors and hospitals (except emergencies), while Medicare Supplement lets you see any doctor who accepts Medicare, anywhere in the country.
  • Medicare Advantage premiums are often lower or zero, but you pay per-visit copays and have an annual out-of-pocket maximum; Medicare Supplement has a higher monthly premium but predictable costs after that.
  • Medicare Advantage plans include prescription drug coverage (Part D) built in; Medicare Supplement does not, so you must enroll in a separate Part D plan.
  • You can switch between Medicare Advantage and Medicare Supplement during the annual open enrollment period (October 15 to December 7) without penalty, but switching from Supplement to Advantage may be harder later if you have health problems.
  • Medicare Advantage plans often cover dental, vision, and hearing; Medicare Supplement does not cover these services at all.

Medicare Advantage: lower upfront cost, network restrictions

Medicare Advantage plans are run by private insurers like Humana, UnitedHealthcare, and Anthem. Most charge zero monthly premium, though some charge $50 to $200 per month. In exchange, you accept a narrower network of doctors and hospitals. If you see an out-of-network provider (except in emergencies), you pay the full bill yourself or a much higher copay.

You pay per visit: typically $10 to $50 for a doctor visit, $50 to $300 for a specialist, and $100 to $500 for a hospital stay. The plan sets an annual out-of-pocket maximum — usually $5,000 to $7,000 — so once you hit that number, the plan covers 100 percent of in-network care for the rest of the year. This ceiling gives you cost predictability if you need a lot of care.

Medicare Advantage plans must include prescription drug coverage (Part D), so you do not buy a separate drug plan. Many plans also cover dental cleanings, vision exams, hearing aids, and fitness programs — benefits Original Medicare does not cover. If these matter to you, Advantage can save you hundreds per year.

The trade-off: you cannot straightforward see any doctor. You need a referral from your primary care doctor to see a specialist. If you travel frequently or move, you may lose your doctor. And if you switch to a Medicare Supplement later, insurers can deny you or charge more if you have developed a health condition in the meantime.

Medicare Supplement: freedom of choice, predictable costs

Medicare Supplement (also called Medigap) is a standardized product. There are ten different plans, labeled A through N, and each one covers the same benefits no matter which insurer sells it. Plan G covers the same things whether you buy it from AARP/UnitedHealthcare or from Cigna. This standardization makes it straightforward to compare prices across insurers.

Most people choose Plan G or Plan N. Plan G covers the Part B deductible ($240 in 2024, though this varies yearly), copays, coinsurance, and excess charges. After you pay your monthly premium — typically $120 to $250 depending on your age and location — you have very few bills left. You see any doctor or specialist who accepts Medicare, anywhere in the United States, with no referrals and no network limits.

Plan N is cheaper (often $80 to $150 per month) but requires you to pay a copay for doctor visits and emergency room visits. Both plans have no annual out-of-pocket maximum, so your costs are capped only by your monthly premium.

You must enroll in a separate Part D prescription drug plan; Medicare Supplement does not include drug coverage. You also pay out of pocket for dental, vision, hearing, and fitness — Medicare Supplement does not cover these at all.

Cost comparison: when Advantage wins, when Supplement wins

If you are healthy and see a doctor once or twice a year, Medicare Advantage is usually cheaper. A zero-premium Advantage plan with two $20 copays costs you $40 per year. The same person on Plan G might pay $1,800 per year in premiums and have almost no other costs. Over a year, Advantage saves $1,760.

If you have chronic conditions — diabetes, heart disease, arthritis — and see multiple specialists, the math flips. Suppose you see your primary doctor 6 times, two specialists 4 times each, and have one hospital stay. On a Medicare Advantage plan with $20 copays and a $300 hospital copay, you pay roughly $280 in copays plus your monthly premium. On Plan G, you pay your monthly premium and almost nothing else. If your Advantage premium is $100 per month, you pay $1,200 plus $280 = $1,480. Plan G at $200 per month costs $2,400 — but you have no surprise bills if you need more care.

The real advantage of Supplement emerges when you hit the Advantage plan's out-of-pocket maximum. Once you reach $5,000 to $7,000 in copays, the plan covers everything. But if you are paying $200 per month for Supplement, you are already committed to $2,400 per year, and you have no ceiling. Very high-cost years favor Advantage; moderate-cost years often favor Supplement.

Network and travel: a major practical difference

If you travel or split time between states, Medicare Supplement is simpler. You see any Medicare-accepting doctor anywhere. If you winter in Arizona and summer in Maine, your coverage follows you without change.

Medicare Advantage plans are regional. Your plan covers doctors and hospitals in your service area. If you travel for a month, you can use emergency care anywhere, but routine care outside your network is your responsibility. Some plans allow you to see out-of-network doctors at a higher copay, but not all. If you move permanently, you must switch plans during the annual enrollment period or wait until the next one.

If you have a long-standing relationship with a specific doctor or specialist, check whether they are in your Advantage plan's network before you enroll. If your doctor is not in the network and you want to keep seeing them, Medicare Supplement is the better choice.

Switching between plans: timing and penalties

You can change from Medicare Advantage to Medicare Supplement (or vice versa) during the annual open enrollment period, October 15 to December 7. Changes take effect January 1. There is no penalty for switching during this window.

If you switch from Medicare Supplement to Medicare Advantage, you can do so anytime. If you switch from Medicare Advantage to Medicare Supplement, you can also switch anytime, but here is the catch: if you have developed a new health condition since you enrolled in Advantage, the Supplement insurer can deny you or charge you more. Some states have protections that limit this, but not all. If you think you might want a Supplement later, switching from Advantage to Supplement sooner rather than later protects you.

If you miss the open enrollment window and want to switch, you may have to wait until the next October. The exception is if you move out of your plan's service area, lose coverage, or have a may have access to life event — in those cases, you may be able to switch outside the window.

Prescription drugs: a key difference

Medicare Advantage includes Part D prescription drug coverage. The plan decides which drugs it covers and at what cost. Some drugs may require prior approval from the plan before the pharmacy will fill them.

If you take expensive medications, check the plan's formulary (the list of covered drugs) before you enroll. If your drug is not covered or is in a high cost tier, the plan may not be a good fit.

Medicare Supplement does not include drug coverage. You must enroll in a standalone Part D plan, which you choose separately. This gives you more flexibility — you can pick the plan that covers your specific drugs at the lowest cost — but it is one more enrollment step and one more monthly bill.

Frequently Asked Questions

Can I switch from Medicare Advantage to Medicare Supplement if I have a pre-existing condition?

Yes, but timing matters. During the annual open enrollment period (October 15 to December 7), you can switch without the Supplement insurer asking about your health. If you switch outside this window, the insurer can deny you or charge more based on your health history. Some states offer limited protections, but they vary. Switching sooner is safer than waiting.

Do I have to use a primary care doctor on Medicare Advantage?

Most Medicare Advantage plans are HMOs, which require you to choose a primary care doctor and get referrals to see specialists. Some plans are PPOs, which let you see specialists without a referral but charge higher copays. Check your plan's rules before you enroll.

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

Your plan's coverage ends on the last day of the month you move. You have 60 days to enroll in a new plan in your new state. If you do not enroll, you lose coverage. You can switch to a Medicare Supplement during this time without the insurer asking about your health.

Is dental or vision coverage worth choosing Medicare Advantage?

It depends on your needs. Medicare Advantage dental usually covers cleanings and exams but not major work like crowns or root canals. Vision covers exams and a small allowance toward glasses or contacts. If you need significant dental work, you will still pay out of pocket. Compare the plan's coverage limits against what you actually need before deciding.

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

No. You can have either Original Medicare with a Supplement, or Medicare Advantage. You cannot have both. If you enroll in Advantage, your Original Medicare coverage ends. If you later switch back to Original Medicare, you can enroll in a Supplement, but the insurer may charge more if you have developed health conditions in the meantime.