One of the biggest decisions you’ll make when enrolling in Medicare is whether to go with a Medicare Supplement (Medigap) plan or a Medicare Advantage (Part C) plan. Both options help cover costs that Original Medicare doesn’t pay for, but they work in fundamentally different ways — and the right choice depends on your health, your budget, your travel habits, and your preferences.
In this guide, we’ll break down exactly how each plan type works, compare costs and benefits side by side, and help you figure out which one makes the most sense for your situation in 2026.
Before diving into the comparison, it helps to understand what Original Medicare (Parts A and B) covers — and what it doesn’t. Original Medicare pays about 80% of approved medical costs, leaving you responsible for the remaining 20% with no annual out-of-pocket maximum. That means a single hospital stay or surgery could cost you thousands, even tens of thousands of dollars.
That’s where supplemental coverage comes in. You have two paths to fill those gaps:
A Medicare Supplement plan — commonly called Medigap — is a private insurance policy that works alongside Original Medicare. You keep Parts A and B, and Medigap pays some or all of the costs that Original Medicare doesn’t cover: deductibles, copayments, and coinsurance.
When you see a doctor or go to the hospital, Original Medicare pays its share first, then your Medigap policy kicks in to cover the remaining costs (depending on the plan you choose). You pay your monthly Medigap premium, and in return, you have highly predictable out-of-pocket costs.
Plan G is the gold standard for new Medicare enrollees. It covers:
The only cost you pay out of pocket with Plan G is the annual Part B deductible, which is set by CMS each year. After that, Plan G covers virtually everything else at 100%.
A Medicare Advantage plan is an all-in-one alternative to Original Medicare, offered by private insurance companies approved by Medicare. When you enroll in Medicare Advantage, you’re still technically in Medicare, but your plan — not the government — manages your coverage and pays your claims.
Medicare pays your Advantage plan a fixed amount per month to cover your care. The plan then provides at least the same benefits as Original Medicare (Parts A and B), and most plans also include:
Many Medicare Advantage plans have $0 monthly premiums (beyond your Part B premium), which is one of their biggest draws. However, you’ll pay copays, coinsurance, and deductibles when you use services.
| Feature | Medicare Supplement (Medigap) | Medicare Advantage (Part C) |
|---|---|---|
| Works with | Original Medicare (Parts A & B) | Replaces Original Medicare delivery |
| Monthly premium | Higher (varies by plan, age, location) | Often $0 (beyond Part B premium) |
| Out-of-pocket costs | Little to none after premium | Copays, coinsurance at time of service |
| Annual out-of-pocket max | Effectively none needed (plan covers gaps) | Required by law (varies by plan) |
| Doctor network | Any doctor accepting Medicare nationwide | Network-based (HMO, PPO, etc.) |
| Referrals needed? | No | Often yes (HMO plans) |
| Prescription drugs | Separate Part D plan required | Usually included |
| Dental, vision, hearing | Not included | Often included |
| Works while traveling | Yes — any Medicare provider in the U.S. | Limited (emergency only outside network area) |
| Guaranteed issue | 6-month Medigap OEP only | Available during AEP and IEP |
This is where the two plan types differ most. Understanding the cost trade-off is essential.
With a Medigap plan like Plan G, you pay a predictable monthly premium (typically $100–$300/month depending on your age, location, and carrier). In exchange, your out-of-pocket costs when you see a doctor or go to the hospital are minimal to zero.
This means your healthcare costs are highly predictable month to month and year to year. Whether you have a healthy year or a year with major surgery, your costs stay roughly the same.
With Medicare Advantage, you might pay $0/month in plan premiums (beyond your Part B premium). But you’ll owe copays and coinsurance each time you use services. A doctor visit might cost $20, a specialist $40, and a hospital stay could run into the thousands before hitting your plan’s out-of-pocket maximum.
If you’re relatively healthy and don’t use many services, Medicare Advantage can be very affordable. But if you have a major health event, costs can add up quickly — though they are capped by the plan’s annual maximum.
This is often the deciding factor for many people.
With a Medigap plan, you can see any doctor or specialist anywhere in the United States who accepts Medicare — and the vast majority do. You never need a referral, and you never have to worry about whether a provider is “in network.” If you travel frequently, split time between states, or want maximum flexibility in choosing your doctors, Medigap provides that freedom.
Medicare Advantage plans use provider networks, similar to employer health insurance. Depending on the plan type:
Medicare Advantage networks can change from year to year. A doctor who is in-network this year may not be next year. Hospitals and specialists can also leave networks. This means you should review your plan every year during the Annual Enrollment Period (October 15 – December 7) to make sure your doctors and medications are still covered.
One area where Medicare Advantage often has the edge is extra benefits that Original Medicare and Medigap simply don’t cover:
If you choose Medigap, you’d need to purchase separate dental, vision, and hearing coverage to get similar benefits. We offer standalone DVH plans that pair well with Medigap — learn more here.
Your Medigap OEP is a one-time, 6-month window that starts the month your Medicare Part B becomes effective. During this period, insurance companies cannot deny you coverage or charge you more because of pre-existing conditions.
This is critical: Once this window closes, insurers can use medical underwriting to deny your application or charge higher rates. In many states, there is no guaranteed right to buy a Medigap policy outside of this window.
Initial Enrollment Period (IEP): The 7-month window around your 65th birthday (or when you first qualify for Medicare).
Annual Enrollment Period (AEP): October 15 – December 7 each year. You can join, switch, or drop a Medicare Advantage plan.
Open Enrollment Period (OEP): January 1 – March 31 each year. If you’re already in a Medicare Advantage plan, you can switch to a different plan or return to Original Medicare.
There’s no one-size-fits-all answer. Here’s a breakdown based on common situations:
If you think you might want a Medigap plan, don’t delay. Your guaranteed-issue Medigap Open Enrollment Period is only 6 months, starting when your Part B becomes effective. After that window closes, you may face medical underwriting — meaning the insurance company can review your health history and potentially deny coverage or charge significantly higher premiums.
You can always switch from Medigap to Medicare Advantage during an enrollment period, but switching from Medicare Advantage to Medigap after your OEP has passed can be difficult or impossible depending on your health and your state’s rules.
Our free 16-chapter Medicare Roadmap explains both plan types in detail, with cost comparisons, checklists, and decision guides.
Download Free Guide →Both Medicare Supplement and Medicare Advantage plans have real advantages. Medigap gives you maximum freedom and predictability at a higher monthly cost. Medicare Advantage gives you lower premiums and extra benefits but with network restrictions and variable out-of-pocket costs.
The best plan for you depends on your unique situation — your health, your doctors, where you live, how you travel, and what you can comfortably budget. As independent brokers licensed in all 50 states, we represent carriers on both sides and can give you an unbiased comparison based on your specific needs.
Our consultations are always free, and there’s never any pressure. Call or text us at 1-855-937-4600 or schedule a call online.
Call or text us for a free, no-obligation consultation. We’ll review your options and find the best plan for your needs and budget.