Medicare Advantage and Medigap are not two flavors of the same product. They are two different systems, and only one of them has a door that locks behind you. Medicare Advantage is a private plan that replaces how Original Medicare pays your bills, usually with a low premium, a network, and an annual out-of-pocket cap. Medigap is a private policy that sits on top of Original Medicare and pays the 20% Medicare leaves you owing, with a higher premium and no network. You cannot have both at the same time. The decision that matters most is not which one is cheaper this year. It is that you can move from Medigap to Medicare Advantage almost any year you want, while moving from Medicare Advantage back to Medigap can be denied outright in most states once your one-time enrollment window closes.
This guide is the head-to-head comparison. If you want the mechanics of Medigap plan letters on their own, read Medicare Supplement (Medigap) Explained 2026. If you are still deciding between Part C and traditional Medicare in general, read Medicare Advantage vs Original Medicare 2026.
The One-Way Door: Why Timing Beats Price
Every other comparison of these two products leads with premiums. That is backwards, because your premium is a decision you can revisit every October. Your eligibility to buy a Medigap policy at all is usually a decision you make once, at 65, and it expires.
Here is the rule. Your Medigap Open Enrollment Period is a single six-month window that starts the first month you are both 65 or older and enrolled in Medicare Part B. During those six months, an insurer must sell you any Medigap plan it offers in your state. It cannot ask about your health, cannot turn you down, and cannot charge you more because of a diagnosis.
After those six months end, federal law no longer protects you. In most states, an insurer can put you through medical underwriting: a health questionnaire, a prescription history check, and sometimes a phone interview. Diabetes with insulin, COPD, a recent cancer treatment, congestive heart failure, or a pending surgery can all result in a flat decline or a rated-up premium.
So the practical shape of the decision is asymmetric:
| Move | When you can do it | Can you be turned down? |
|---|
| Medigap to Medicare Advantage | Annual Enrollment, Oct 15 to Dec 7 | No. Medicare Advantage plans cannot medically underwrite |
| Medicare Advantage to Original Medicare | Oct 15 to Dec 7, or Jan 1 to Mar 31 | No. You can always return to Original Medicare |
| Medicare Advantage to Original Medicare plus a Medigap policy | Any time you can apply | Yes, in most states, unless a guaranteed issue right applies |
Dropping Medicare Advantage is easy. Landing softly on a Medigap policy afterward is the part that can fail.
2026 Cost Comparison
These are the confirmed 2026 federal figures. Everyone pays the Part B premium regardless of which path they pick.
| Cost item | 2026 amount |
|---|
| Part B standard premium | $202.90 per month |
| Part B annual deductible | $283 |
| Part A hospital deductible | $1,736 per benefit period |
| Part A coinsurance, days 61 to 90 | $434 per day |
| Part A coinsurance, lifetime reserve days | $868 per day |
| Skilled nursing coinsurance, days 21 to 100 | $217 per day |
| Part D out-of-pocket cap | $2,100 |
| Maximum Part D deductible | $615 |
Now the two paths side by side, using typical figures for a 65-year-old in average health:
| Medicare Advantage | Original Medicare + Medigap Plan G |
|---|
| Average plan premium (2026) | About $11 per month | Roughly $130 to $400 per month, varies widely by state and age |
| Part D drug coverage | Usually built in | Separate plan, typically $15 to $60 per month |
| Part A deductible | Plan-specific copays instead | Covered by Plan G |
| Part B deductible | Not applicable | You pay the $283 yourself |
| Part B coinsurance (the 20%) | Copays per service | Covered by Plan G |
| Annual out-of-pocket cap | Federal max $9,250 in-network for 2026, plan average around $6,100 | No formal cap, but Plan G leaves almost nothing uncovered after the $283 |
| Doctor access | Network only, referrals common in HMOs | Any provider in the country that accepts Medicare |
| Prior authorization | Common for imaging, surgery, skilled nursing | Rare in Original Medicare |
| Dental, vision, hearing, gym | Often included | Not included, buy separately |
The honest read: Medicare Advantage almost always wins on cash flow in a healthy year. Medigap almost always wins on predictability in a bad year. A Plan G holder in 2026 who has a stroke, three hospitalizations, and six months of rehab pays $283 plus premiums. A Medicare Advantage member in the same year could pay up to the plan's out-of-pocket maximum, which is thousands of dollars, and may fight prior authorization denials along the way.
Guaranteed Issue Rights: The Escape Hatches
Federal law creates a short list of situations where an insurer must sell you a Medigap policy even after your six-month window closed. These are called guaranteed issue rights. The most useful ones:
The Medicare Advantage trial right. If you joined a Medicare Advantage plan when you first became eligible for Medicare at 65, you get 12 months to change your mind. Leave the plan inside that first year and you can buy any Medigap policy sold in your state with no health questions. This is the single most valuable protection in the system and it is used far less than it should be, because the clock is invisible. You must apply no earlier than 60 days before your Medicare Advantage coverage ends and no later than 63 days after it ends.
The dropped-Medigap trial right. If you had Original Medicare with a Medigap policy, dropped the Medigap to try Medicare Advantage for the first time, and want out within 12 months, you can return to your former Medigap policy if it is still sold. If it is not, you can buy certain other plan letters.
Your plan leaves or you move. If your Medicare Advantage plan exits your county, ends its contract, or you move out of its service area, you get a guaranteed issue right, generally for 63 days.
Your plan misled you or broke the rules. If the plan violated its contract or was marketed to you improperly, you may qualify. This one requires documentation.
Outside of those, if you have been in a Medicare Advantage plan for four years and now want Plan G, you are applying with your medical history on the table.
State Rules That Override the Federal Default
A minority of states are more generous than federal law, and where you live can completely change this decision.
Continuous or annual guaranteed issue: Connecticut and New York require insurers to sell Medigap policies year-round with no health questions at any age. Massachusetts and Maine have their own annual open windows. Minnesota is adding an annual enrollment window in 2026. In these states, the choice is genuinely reversible and you can pick Medicare Advantage at 65 with much less risk.
Birthday rule states: As of 2026 roughly 16 states, including California, Idaho, Illinois, Kentucky, Louisiana, Maryland, Nevada, Oklahoma, Oregon, and several others, give existing Medigap policyholders a short window around their birthday to switch to another Medigap plan of equal or lesser benefits without underwriting. Important limit: birthday rules almost always apply to people who already have a Medigap policy. They usually do not let a Medicare Advantage member jump into Medigap.
Because these rules change and vary in the details, confirm your own state's version with your State Health Insurance Assistance Program (SHIP) before you count on it. Every state has a free SHIP counselor.
Who Should Choose Which
Lean Medicare Advantage if:
- Your budget cannot absorb a $150 to $400 monthly Medigap premium
- You are healthy, your doctors are all in one local network, and you rarely travel
- You value bundled dental, vision, hearing, and drug coverage in one card
- You live in Connecticut, New York, Massachusetts, or Maine, where you can move to Medigap later without underwriting
- You qualify for a Special Needs Plan because you have both Medicare and Medicaid
Lean Medigap if:
- You have a chronic condition, a family history that worries you, or an expected surgery
- You split time between states, travel often, or want access to a distant specialty hospital
- You want a predictable annual cost even in a catastrophic year
- You cannot tolerate prior authorization delays for imaging or skilled nursing
- You are in your six-month Medigap window right now and are unsure, because entering Medigap and leaving later is far easier than the reverse
If you fall in the middle, one strategy is worth knowing: buy Medigap during your six-month window and switch to Medicare Advantage later if the premium becomes unaffordable. That order keeps your options open. The reverse order can close them permanently.
How to Switch From Medicare Advantage to Medigap
If you have decided to move, do it in this order. Getting the sequence wrong can leave you with a coverage gap.
- Check whether you have a guaranteed issue right first. Count the months since your Medicare Advantage plan started. If you are inside 12 months of your first-ever enrollment at 65, you have a trial right. Call 1-800-MEDICARE to confirm.
- Apply for the Medigap policy before you cancel anything. Get a written approval in hand. If you are underwritten and declined, you want to still be enrolled in your current plan.
- Apply for a stand-alone Part D drug plan. Medigap does not cover drugs, and your Medicare Advantage plan probably did. Skipping this creates a Part D late enrollment penalty that lasts for life.
- Disenroll from Medicare Advantage during Annual Enrollment (Oct 15 to Dec 7) or the Medicare Advantage Open Enrollment Period (Jan 1 to Mar 31). Enrolling in a stand-alone Part D plan usually triggers disenrollment automatically.
- Confirm your effective dates line up. Medigap coverage should start the same day Original Medicare resumes, normally January 1 or the first of the month after a spring switch.
Frequently Asked Questions
Can I have Medicare Advantage and Medigap at the same time?
No. It is illegal for an insurer to sell you a Medigap policy while you are enrolled in a Medicare Advantage plan, except when you are about to leave the Advantage plan. Medigap only pays alongside Original Medicare.
Can I be denied a Medigap policy if I have a health condition?
Yes, in most states, once your six-month Medigap Open Enrollment Period has ended and no guaranteed issue right applies. Insurers can review your medical history and prescriptions and decline you or charge more. Inside your six-month window, or with a valid guaranteed issue right, they cannot.
How long do I have to switch back from Medicare Advantage to Medigap?
If Medicare Advantage was your first coverage choice at 65, you have a 12-month trial right, and you must apply for Medigap no more than 60 days before the Advantage plan ends or 63 days after it ends. Beyond that, there is no federal deadline because there is no federal right, only underwriting.
Is Medigap worth the higher premium in 2026?
It depends on your risk tolerance. Plan G leaves you owing the $283 Part B deductible and essentially nothing else, while a Medicare Advantage plan can expose you to several thousand dollars in a heavy year. If a $6,000 medical year would be a crisis for your household, the Medigap premium buys real protection. If it would merely be annoying, Medicare Advantage keeps more cash in your pocket most years.
Does Medigap cover prescription drugs?
No. Medigap policies sold since 2006 cannot include drug coverage. You need a separate Part D plan, which has a $2,100 out-of-pocket cap in 2026.
What if I moved to Medicare Advantage years ago and now want Medigap?
Apply and answer the health questions honestly. Some insurers underwrite more leniently than others, and an independent broker who represents multiple carriers can tell you which ones in your state are likely to accept your history. Also check whether your state has continuous guaranteed issue or a birthday rule that applies to you.
Do Medigap premiums go up as I age?
That depends on how the policy is priced. Attained-age policies rise as you get older. Issue-age policies are set by your age at purchase. Community-rated policies charge everyone in the state the same regardless of age. Attained-age is the most common and the cheapest at 65, which is why some people are priced out of Medigap in their late 70s, exactly when underwriting would block them from shopping for a cheaper one.
