Direct answer: In the Medigap vs Medicare Advantage choice, you can pick only one. Medigap sits on top of Original Medicare and pays some or most of your share of the bills. Medicare Advantage replaces the way you get Part A and Part B, usually with a network and its own copays.
You pay the $202.90 Part B premium on either path in 2026. The real choice is how you pay for everything else. With Medigap, you pay a higher monthly premium and owe little when you get sick. With Advantage, you often pay a small or $0 plan premium, then pay copays as you use care, up to a yearly limit.
Timing is the hard part. Your easiest chance to buy Medigap comes once, in the six months after you are 65 and have Part B. If you miss it, a company in most states can ask about your health and turn you down.
If you are reading this at the kitchen table, worried about a parent, take a breath. These rules do not change from person to person, and a few simple checks will show which path fits.
What are the two paths?
Path A is Original Medicare plus Medigap. Medigap is private insurance that helps pay what Original Medicare leaves you to pay. You can see any doctor or hospital in the country that takes Medicare. Policies sold today do not cover drugs, so most people add a separate Part D plan.
Path B is Medicare Advantage, also called Part C. A private plan that contracts with Medicare runs your Part A and Part B benefits. Most plans include drug coverage. Every plan must set a yearly limit on what you pay for covered Medicare services. In return, many plans use a network. Some plans also need a referral or an OK in advance before certain care.
Medigap plans come in letters, such as G and N. In most states, the same letter has the same basic benefits at every company, according to Medicare.gov. Only the price changes. Three states set up Medigap their own way, so check your state’s rules.
Swipe sideways to see every column.
| Original Medicare + Medigap | Medicare Advantage | |
|---|---|---|
| Part B premium | You pay it | You pay it |
| Plan premium | Set by the company; varies by letter, age and ZIP | Often low or $0; can change each year |
| Doctors | Any that take Medicare | Usually a network |
| Drug coverage | Separate Part D plan | Usually built in |
| Yearly spending cap | None in Original Medicare; Medigap fills gaps | Required in every plan |
| Advance OK for care | Seldom needed | Common for some services |
| Dental and vision | Not covered by Medigap | Some plans offer extras |
Why can’t you have both?
Medicare.gov is clear on this. Medigap cannot pay Advantage copays, deductibles or premiums. It is illegal for a company to sell you Medigap if it knows you are in Advantage, unless you are switching back to Original Medicare.
There is a simple reason for the rule. Medigap pays the shares that only exist in Original Medicare. An Advantage plan sets its own copays, so a Medigap policy would have nothing to pay.
If you keep a Medigap policy after joining Advantage, you pay for coverage you cannot use. If you drop it, you may not get it back later. So act in the right order.
In my 18 years in insurance marketing, I have seen ads blur these two on purpose. An ad promises supplement benefits, and the phone line sells an Advantage plan. Medicare.gov says it is illegal to call an Advantage plan a Medigap policy. If you hear that on a call, end the call.
What do the 2026 numbers say?
Here are the federal costs that sit under both paths. They come from the CMS 2026 fact sheet and Medicare.gov’s cost page.
- Part B premium: $202.90 a month for most people. That is $2,434.80 a year.
- Part B deductible: $283 a year. After that, you pay 20% of most Part B bills.
- Part A hospital deductible: $1,736 per benefit period.
- Hospital days 61 to 90: $434 a day.
- Skilled nursing days 1 to 20: $0. Days 21 to 100: $217 a day.
Higher earners pay more. If your 2024 income was above $109,000 single or $218,000 joint, Part B starts at $284.10 a month. SSA explains the income brackets.
Here is a worked example. Say you spend five days in the hospital. Then you spend 30 days in a rehab center. You also have $2,000 in doctor bills under Part B.
Swipe sideways to see every column.
| Cost piece | Original Medicare alone | With Plan G | With Plan N |
|---|---|---|---|
| Part A deductible | $1,736 | $0 | $0 |
| Rehab days 21 to 30 (10 × $217) | $2,170 | $0 | $0 |
| Part B deductible | $283 | $283 | $283 |
| 20% of the other $1,717 | $343.40 | $0 | $0, plus some copays |
| Total before premiums | $4,532.40 | $283 | $283 plus copays |
For Plan N, Medicare.gov’s benefit chart says you may owe up to $20 for some office visits. You may owe up to $50 for an ER visit that does not lead to a hospital stay.
An Advantage plan would charge its own hospital and rehab copays. Those amounts differ by plan. You find them in the plan’s Evidence of Coverage, a long booklet each plan must publish.
The fine print: a window that does not come back
Your Medigap Open Enrollment Period lasts six months. It starts the first month you have Part B and are 65 or older. During that time, a company cannot turn you down or charge you more for health problems.
A company can still make you wait up to six months for coverage of a health problem you already had. Prior coverage can shorten that wait. During the wait, Original Medicare still pays its share.
This window is separate from the fall Open Enrollment, which runs Oct. 15 to Dec. 7. That fall window lets you change plans. It does not give you a second Medigap window.
After your window closes, no company has to sell you a policy. A few events give you a special right to buy, such as an Advantage plan leaving your area. You generally must apply within 63 days after the old coverage ends, according to Medicare’s Medigap guide.
Two more rules matter:
- Plans C and F are closed to anyone who first became eligible for Medicare on or after Jan. 1, 2020. Plan G is the closest match, minus the Part B deductible.
- Trial rights give some first-time Advantage members 12 months to switch back and buy Medigap. That is a way back. It does not let you keep both.
Still working at 65? Your Medigap window starts when Part B starts, so the timing needs care. See Medicare and working past 65.
Can’t you just try Advantage and switch later?
A common tip is to start with a $0 Advantage plan, since you can switch every fall. You can switch back to Original Medicare. Buying a Medigap policy after you switch back is the hard part. Outside your window or a special right, a company may ask health questions and say no.
From the marketing side, the line about switching anytime is the one I trust least. It is true for the Medicare part and often false for the Medigap part.
If you are healthy and on a tight budget
Advantage can cost less in a good year. Do the bad-year math too. Add the plan premium to the plan’s yearly limit. Compare that number to a Medigap premium plus a Part D premium.
If you have a long-term illness
Big, steady bills often favor Medigap. You can see specialists without network limits. Your costs are easier to predict.
If you live in two places
Many Advantage plans cover routine care only near home. Original Medicare works in every state, so check the network before you sign.
If your income is low
You may qualify for help with Part B and drug costs. Read about Medicare Savings Programs and Extra Help and Special Needs Plans.
Where the money goes
Insurance companies pay agents to sell both paths. Medicare also pays Advantage plans each month for every member. That steady payment is why so much fall advertising points to Advantage.
From my years buying and selling leads, I can say this plainly. The phone number on a benefits ad often goes to a call center. The person who answers may sell only a few companies’ plans. Agents must tell you if they do not offer every plan in your area. Ask them directly.
Free counselors at your State Health Insurance Assistance Program do not sell plans. They can check the same choices with you at no cost.
Related: Medicare Advantage vs Original Medicare, Medigap Plan G vs Plan N, and Medigap open enrollment at 65.
Seven moves before you sign
- List the doctors and hospitals you will not give up. Check each one in the plan’s network using Medicare Plan Compare.
- Write your Medigap window dates on the calendar. Count six months from your Part B start date.
- Enter every drug you take in Plan Compare. Do this for both a Part D plan and any Advantage plan.
- Get Medigap prices for the same letter from several companies. The benefits match, so compare the price and how it has risen over time.
- Read the Advantage plan’s Evidence of Coverage. Find the yearly limit, the hospital and rehab copays, and which services need an OK in advance.
- Do the worst-year math for each path. Add the premiums for 12 months plus the most you could pay out of pocket.
- Book a free SHIP session before you enroll. Bring your list of doctors and drugs.
What not to do
- Do not cancel Medigap until your new coverage is confirmed in writing.
- Do not enroll on the first call from an ad.
- Do not treat the fall window as a second Medigap chance.
Frequently asked questions
Can I have Medigap and Medicare Advantage at the same time?
No. You choose one path. Medigap cannot pay Advantage copays, deductibles or premiums. It is illegal for a company to sell you Medigap if it knows you are in Advantage, unless you are switching back to Original Medicare. If you keep both, you pay for a Medigap policy you cannot use.
When is the Medigap Open Enrollment Period?
It lasts six months. It starts the first month you are 65 or older and have Part B. During those months, a company cannot refuse you or charge more because of your health. This window is separate from the fall Open Enrollment Period. After it ends, companies in most states can ask health questions.
Do I still pay the Part B premium with either path?
Yes. You keep paying Part B on both paths. For most people in 2026, that is $202.90 a month. Higher earners pay more because of an income charge called IRMAA. With Medigap, you also pay the Medigap premium. With Advantage, you pay any plan premium the plan charges.
Why can’t I buy Plan F or Plan C?
If you first became eligible for Medicare on or after Jan. 1, 2020, those two letters are closed to you. People who were eligible before that date may still buy them where companies sell them. For newer enrollees, Plan G is the closest match. The main difference is that Plan G does not pay the $283 Part B deductible.
Is a $0 Advantage premium the same as free coverage?
No. You still pay Part B, plus IRMAA if your income is high. You also pay the plan’s copays and coinsurance when you get care, up to the plan’s yearly limit. The $0 covers only the plan premium, and plans can change that premium and their copays each year.
Your next step
Find your Part B start date today and count six months forward. That date matters more than any ad you will see this fall. Then run your doctors and drugs through Plan Compare and book a free SHIP session. Make your choice before your Medigap window closes.
Sources
- Medicare.gov: What's Medicare Supplement Insurance (Medigap)?
- Medicare.gov: Compare Medigap plan benefits
- Medicare.gov: Medicare Advantage plans
- Medicare.gov: Medicare costs
- CMS: 2026 Medicare Parts A and B premiums and deductibles
- Medicare.gov: Choosing a Medigap Policy (Publication 02110)
- SSA: Medicare premiums and income-related amounts
- ACL: State Health Insurance Assistance Program