Once you understand the basics of Original Medicare, the next major decision most people face is how to cover its gaps — the coinsurance, copays, and uncapped out-of-pocket exposure that Parts A and B leave behind. There are two fundamentally different paths: Medicare Advantage (Part C) and Medigap (Medicare Supplement Insurance). Both solve the same underlying problem, but in very different ways, and the choice between them isn’t fully reversible without risk — which is exactly why it’s worth understanding thoroughly before deciding.
The Core Difference
Medicare Advantage replaces Original Medicare — you get your Part A and Part B benefits (and usually Part D and extra benefits) through a private insurance company, typically within a provider network. Medigap works alongside Original Medicare — you keep Parts A and B exactly as they are, and the Medigap policy pays some or all of what Original Medicare doesn’t, with no network restrictions.
Side-by-Side Comparison
| Medicare Advantage | Medigap | |
|---|---|---|
| Monthly premium | Often lower, sometimes $0 | Generally higher |
| Provider network | Usually HMO/PPO restricted | Any provider nationwide accepting Medicare |
| Drug coverage | Usually bundled in | Requires separate Part D plan |
| Extra benefits | Often dental, vision, hearing, fitness | Typically none |
| Out-of-pocket maximum | Yes, plan-specific annual cap | No single cap, but very predictable cost-sharing |
| Referrals | May be required for specialists (HMO) | Not required |
| Travel flexibility | Limited outside plan service area | Coverage travels with you nationwide |
Cost: Premium Isn’t the Whole Picture
The most common mistake in comparing these two options is looking only at the monthly premium. A $0-premium Medicare Advantage plan can cost more in a year with a major health event than a Medigap plan with a meaningful monthly premium, once you account for the Medicare Advantage plan’s copays and coinsurance up to its out-of-pocket maximum. To compare fairly:
- Add up 12 months of premiums for whichever option you’re considering, plus the standard Part B premium ($202.90/month in 2026) either way.
- Estimate your likely out-of-pocket costs based on your actual healthcare use — office visits, any planned procedures, regular prescriptions.
- For Medicare Advantage, check the plan’s specific out-of-pocket maximum as your worst-case cost ceiling for the year.
For the full 2026 cost figures to plug into this estimate — including IRMAA and Part A costs — see our complete cost breakdown.
Networks and Provider Access
If you have specific doctors or a hospital system you want to keep, Medicare Advantage requires verifying they’re in-network — directly with both the plan and the provider’s office, not just from plan marketing materials. Medigap sidesteps this entirely: since it works alongside Original Medicare rather than replacing it, any provider nationwide who accepts Medicare is available to you, with no network restrictions and no referrals required for specialists.
This matters most for people who travel frequently, split time between states, or simply want maximum flexibility in choosing providers over time.
Who Each Option Tends to Fit Best
Medicare Advantage tends to fit people who are comfortable with a provider network, want lower monthly premiums, value bundled extra benefits like dental and vision, and are generally in good health or comfortable relying on the plan’s annual out-of-pocket maximum as their cost ceiling.
Medigap tends to fit people who prioritize predictable costs and maximum provider flexibility over premium savings, who travel or split time between locations, or who have ongoing health needs where unpredictable copays and coinsurance under Medicare Advantage would be a bigger concern than a higher fixed monthly premium.
The Decision Isn’t Fully Reversible
This is the detail that trips people up most: switching from Medicare Advantage back to Original Medicare plus a Medigap policy later isn’t guaranteed to go smoothly. Outside your one-time Medigap Open Enrollment Period (the 6-month window starting the month you’re both 65+ and enrolled in Part B) or a Guaranteed Issue Right triggered by specific circumstances, Medigap insurers in most states can use medical underwriting — meaning they can deny coverage entirely or charge more based on your health at that point. That’s a meaningful reason to treat this as a considered decision the first time, not something to default into casually.
How a Licensed Agent Can Help
Because this decision depends heavily on your specific doctors, prescriptions, health status, and budget — not a one-size-fits-all answer — working through it with a licensed insurance agent can help you avoid a choice you later regret. A good agent walks through your actual situation rather than pushing a specific product.
See our full coverage options guide for more on comparing these two paths, or start with What Is Medicare? if you want the foundational overview first.
Ready to Compare Your Options?
Kayla Price is a licensed insurance agent (NPN 18530055) offering free, no-pressure consultations. Call (866) 648-1578 to talk through your specific situation.