One of the most important decisions when turning 65 is choosing between Medicare Supplement (Medigap) and Medicare Advantage. Many people get confused because both options "complete" Original Medicare, but they work very differently.
This guide explains the key differences so you can make the right decision based on your health, budget and lifestyle.
The fundamental difference
Medicare Supplement works alongside Original Medicare to pay expenses that Medicare doesn't cover. Medicare Advantage replaces Original Medicare with a private plan that includes additional coverage. You cannot have both at the same time.
What is Medicare Supplement (Medigap)?
Medicare Supplement plans, also called Medigap, are private insurance plans that pay the "gaps" of Original Medicare: deductibles, copayments and coinsurance that you would otherwise pay out of pocket.
With a good Medigap plan, you can go to any doctor or hospital in the US that accepts Medicare, without network restrictions. This is especially valuable if you travel frequently or have specialists outside your area.
Medigap plans are standardized: Plan G is the same with all insurance companies; the only difference is the price. The most popular plans in Florida are Plan G and Plan N.
What is Medicare Advantage?
Medicare Advantage (Part C) replaces Original Medicare. You receive your Part A and B coverage through a private insurer, which usually also includes medications (Part D), dental, vision and more.
Advantage plans work like an HMO or PPO: you have a network of providers and need referrals to specialists in most HMO plans. Many plans have a $0 premium, but you pay copayments when you use services.
Detailed Comparison
| Feature | Medicare Supplement | Medicare Advantage |
|---|---|---|
| Monthly premium | $80–$300/month (depending on plan and age) | $0–$80/month |
| Copayments when using services | Very low or $0 (depending on plan) | $10–$50 per visit |
| Doctor network | Any doctor accepting Medicare | Plan network (HMO/PPO) |
| Dental coverage | Not included — you need a separate plan | Included in most |
| Medication coverage | You need a separate Part D plan | Usually included |
| Out-of-pocket maximum | Practically $0 with Plan G | $3,000–$8,850/year |
| Coverage outside the USA | Some plans include | Generally not |
| Estimated total annual cost | $1,200–$3,600 in premiums + Part B deductible | $0 in premiums but more copayments |
When is Medicare Supplement Right for You?
Choose Medigap if...
Choose Medicare Advantage if...
The Underwriting Problem with Medigap
Here's one of the most important points that few people know about: when you enroll in Medicare Supplement outside the initial period (the 6 months after turning 65 and getting Part B), insurers can reject you or charge you more for pre-existing conditions.
This means that if you start with Medicare Advantage and later want to switch to Medigap, it can be difficult or very expensive if you have medical conditions. That's why it's critical to make the right decision from the beginning.
Golden Rule
If you have chronic conditions that will require frequent care and want maximum protection, consider enrolling in Medigap during your 6 months of guaranteed enrollment when you turn 65. Changing after is harder.
The Real Cost: Which is Cheaper Long-Term?
Medicare Advantage looks cheaper because of the $0 premium, but the real cost depends on how much you use insurance. Let's look at two scenarios:
- Healthy person: With Medicare Advantage at $0/month and occasional copayments, you could spend $300–$600 per year. With Medigap Plan G at $150/month plus Part B deductible ($240 in 2025), you'd spend about $2,040. Advantage wins.
- Person with chronic conditions: With Medicare Advantage you could hit the out-of-pocket maximum of $6,000–$8,000 in a hospitalized year. With Medigap Plan G, after the Part B deductible of $240, you practically pay nothing more. Medigap could save thousands.
What About Medications?
With Medicare Supplement you need to buy a separate Part D plan for medications. With Medicare Advantage, most plans include medication coverage (MAPD). However, not all plans cover the same drugs, so always check the formulary before enrolling.
Our Recommendation
There is no universal answer. If you have diabetes, high blood pressure, heart disease or other chronic conditions, talk to an advisor before choosing. A mistake in this decision could cost you thousands of dollars per year.
