Medigap vs Medicare Advantage: how the two routes compare

Key points

• There are two routes. You can keep Original Medicare (Part A and Part B) and add a Medigap policy and a separate Part D drug plan. Or you can join a Medicare Advantage plan, a private plan that delivers your Part A and Part B benefits and usually includes drug coverage.
• Original Medicare with Medigap lets you use any doctor or hospital in the U.S. that takes Medicare, but you pay a Medigap premium on top of the Part B premium. Medicare Advantage usually means a network, and the plan may require referrals and prior approval, but every plan has a yearly cap on what you pay for covered services: for HMO and PPO plans, no more than $9,850 in network in 2027.
• Timing matters more than most people expect. Federal law gives you one 6-month Medigap Open Enrollment Period, starting the first month you are 65 or older and have Part B. In that window an insurer cannot turn you down or charge you more because of your health. After it, outside a few specific situations, it can.
• We do not recommend plans, insurers or agents. Free one-on-one help comes from your State Health Insurance Assistance Program (SHIP), which is not connected to any insurance company.

The choice between Medigap and Medicare Advantage is a choice between two ways of paying for the same Medicare benefits. One adds a monthly Medigap premium in exchange for a free choice of doctors and, depending on the plan letter, small and predictable bills. The other trades a network and plan rules for a yearly cap on a bad year and, with some plans, a $0 premium. Neither is right for everyone. This guide lays out the federal rules so you can see what you are trading. It is part of our Medicare guide.

These are federal rules. States can add their own Medigap rules, and three states run Medigap differently; we flag where that matters.

What is the difference between Medigap and Medicare Advantage?

Medigap, also called Medicare Supplement Insurance, is a private policy that sits on top of Original Medicare. It only helps pay costs that Original Medicare does not cover, such as the 20% coinsurance for Part B services or the Part A hospital deductible, depending on the plan letter. Medigap only works with Original Medicare. It does not include drug coverage; for that you join a separate Part D plan.

Medicare Advantage, also called Part C, is another way to get your Part A and Part B coverage. The plans are Medicare-approved plans run by private companies, they must follow Medicare’s rules, and most include Part D drug coverage. Out-of-pocket costs vary from plan to plan, and they may offer extras that Original Medicare does not cover, such as some vision, hearing and dental services.

You cannot combine the two. If you are in Medicare Advantage, you cannot use a Medigap policy to pay the plan’s copays, deductibles or premiums, and it is illegal for anyone to sell you a Medigap policy unless you are switching back to Original Medicare.

In both cases you keep paying the Part B premium. In 2026 the standard Part B premium is $202.90 a month. CMS had not published the 2027 Part A and Part B amounts when we checked on November 4, 2026.

Medigap vs Medicare Advantage at a glance

Question	Original Medicare plus Medigap	Medicare Advantage
Which doctors and hospitals?	Any in the U.S. that take Medicare	Usually the plan’s network and service area, except emergencies; some plans pay out of network at a higher cost
Referrals and prior approval?	In most cases, none needed	The plan may require a referral to see a specialist and approval before some services
Yearly cap on what you pay?	None in Original Medicare; Medigap pays most or all of the gap, depending on the letter	Yes, every plan has one; for HMO and PPO plans, up to $9,850 in network in 2027
Premiums	Part B premium, Medigap premium and a Part D premium	Part B premium, plus the plan’s premium if it has one; some plans charge $0
Drug coverage	Separate Part D plan	Included in most plans
Extras such as dental or vision	Not covered by Medigap	Some plans offer some
Emergencies abroad	Plans C, D, F, G, M and N pay 80% up to plan limits	Generally not covered; some plans offer it as an extra
Can you switch later?	Yes, to Medicare Advantage each fall	Yes, to Original Medicare, but a Medigap insurer may then turn you down

The last row is the one people miss. Moving from Medigap to Medicare Advantage is easy. Moving back can be hard, and the next sections explain why.

How much can you pay out of pocket?

Original Medicare alone has no yearly limit. For most Part B services you pay 20% of the Medicare-approved amount after the yearly deductible, $283 in 2026, and there is no ceiling. For a hospital stay, Part A has its own deductible, $1,736 per benefit period in 2026.

Medigap fills most of that gap, depending on the plan letter. All Medigap plans pay the Part B coinsurance, in full for most letters, 50% for Plan K and 75% for Plan L. Only Plans C and F pay the Part B deductible, and people new to Medicare since January 1, 2020 cannot buy those two. Plans K and L have their own yearly out-of-pocket limits, $8,000 and $4,000 in 2026. Plan N pays the Part B coinsurance except for copays of up to $20 for some office visits and up to $50 for an emergency room visit that does not lead to an inpatient admission. The high-deductible versions of Plans F and G make you pay Medicare-covered costs up to a deductible before the policy pays anything: $2,950 in 2026 and $3,050 in 2027.

Medicare Advantage plans cap what you pay. Every plan has a yearly limit on what you pay for covered Part A and Part B services. Once you reach it, you pay nothing more for covered services for the rest of the year. CMS sets the highest limit a plan may use. For 2027 it is $9,850 for in-network services, $600 more than the 2026 limit of $9,250. A PPO plan, which covers out-of-network care, must also have a combined in- and out-of-network limit for all Part A and Part B services, no higher than $14,800 in 2027. A plan can set a lower limit. Medical Savings Account (MSA) plans follow a different rule: the plan starts paying for covered Part A and Part B costs only after you meet a yearly deductible, which varies by plan, and then pays them in full. Your plan’s own limit is in its Annual Notice of Change, which plans send by September 30, and its Evidence of Coverage.

A worked example: one expensive year

Here is a hypothetical expensive year: $60,000 of Medicare-approved Part B charges. We used the 2026 deductible, because the 2027 figure was not out yet. Premiums are left out on purpose: they vary by insurer, state, age and plan, and we do not quote any plan’s price.

Route	What you pay for those Part B services
Original Medicare alone	$283 deductible plus 20% of the remaining $59,717 ($11,943.40): $12,226.40
Original Medicare plus Medigap Plan G	The $283.00 Part B deductible; Plan G pays the 20%
Medicare Advantage	The plan’s copays and coinsurance, but in-network costs for covered services stop at the plan’s limit, at most $9,850 in 2027

Double the bill to $120,000 and the Original Medicare share rises to $24,226.40. A smaller year, $10,000 of approved charges, costs $2,226.40 with Original Medicare alone. That open-ended exposure is the gap Medigap is designed to fill.

The trade looks like this. Medigap costs you a premium every month, in good years and bad, and in return the bills are usually smaller and more predictable, depending on the letter. Medicare Advantage may cost less in premiums, and some plans charge $0, but in a bad year you pay copays and coinsurance up to the plan’s limit, and you work within its network and approval rules. Which matters more depends on your health, your doctors, your budget and how much uncertainty you can live with. For what each part of Medicare costs on its own, see how much Medicare costs, and for drug plans, Medicare Part D costs. In 2027 the Part D deductible can be no more than $700 and the yearly out-of-pocket cap on drugs is $2,400, up from $615 and $2,100 in 2026.

When can you buy a Medigap policy?

Your Medigap Open Enrollment Period is 6 months long and happens once. It starts the first month you have Part B and are 65 or older, and it does not repeat every year. The rule is in federal law, section 1882(s) of the Social Security Act.

During those 6 months, a Medigap insurer cannot refuse to sell you any policy it offers, cannot use medical underwriting to decide whether to accept you, and cannot charge you more because of health problems. In some cases it can make you wait up to 6 months before the policy covers costs for a health problem you already had, but not if you had at least 6 months of continuous creditable coverage before. The insurer can tell you whether your earlier coverage counts.

After the window closes, an insurer can say no. Outside your Medigap Open Enrollment Period you may pay more, you may have fewer choices, and an insurer can refuse to sell you a policy if you do not meet its medical underwriting rules. The exceptions are a short list of situations where federal law gives you a right to buy. Medicare calls these “guaranteed issue rights”. In those situations the insurer must sell you a policy, must cover your pre-existing conditions, and cannot charge you more because of past or present health problems.

States can add rules. Some states give extra Medigap enrollment periods, including for people under 65. Massachusetts, Minnesota and Wisconsin standardize Medigap differently from the lettered plans. If you have Medicare before 65 because of a disability, you may not be able to buy a Medigap policy until you turn 65, depending on your state. Your State Insurance Department can tell you what applies where you live.

If you are still working and delay Part B, your Medigap window does not start until Part B does. See when to apply for Medicare and whether you need Medicare if you have employer insurance.

Can you switch from Medicare Advantage back to Original Medicare?

Yes. The switch itself is easy. Getting a Medigap policy afterward is the hard part.

When you can switch. During Medicare Open Enrollment, October 15 to December 7, 2026 for 2027 coverage, you can move between Original Medicare and Medicare Advantage or change plans. From January 1 to March 31, 2027, people already in a Medicare Advantage plan can switch to a different Medicare Advantage plan or go back to Original Medicare and join a drug plan; you get one change in that period. Our Medicare open enrollment guide covers the dates in detail.

The Medigap catch. Going back to Original Medicare does not, by itself, give you a federal right to buy Medigap. Unless a “guaranteed issue right” applies, the insurer can review your health and turn you down. If you drop Medigap to join Medicare Advantage and later want to come back, you may not be able to get your Medigap policy back.

The two trial rights. Federal law gives a one-year trial in two cases:

1. You joined a Medicare Advantage plan when you were first eligible for Medicare at 65, and within the first year you decide to switch to Original Medicare. You can buy any Medigap policy sold in your state.
2. You dropped a Medigap policy to join a Medicare Advantage plan for the first time, you have been in the plan less than a year, and you want to go back. You can get the same Medigap policy back if the same insurer still sells it.

There are a few other situations, for example when your Medicare Advantage plan leaves Medicare, stops giving care in your area, or you move out of its service area, and you switch to Original Medicare. Outside those, a move back can leave you on Original Medicare with no supplemental coverage and the open-ended 20% from the example above. That is the main reason the first choice at 65 deserves the most care.

What do Medigap plans cover?

Medigap plans are standardized by letter: A, B, C, D, F, G, K, L, M and N in most states. All plans with the same letter offer the same basic benefits, no matter where you live or which insurer sells it. Price is the only difference between policies with the same letter. Some states also sell Medicare SELECT policies, standardized plans that may require you to use network hospitals and sometimes network doctors.

A few rules to know:

• Plans C and F are closed to people new to Medicare on or after January 1, 2020. They can buy Plans D and G instead, which give the same benefits except the Part B deductible.
• Skilled nursing facility coinsurance is paid in full by Plans C, D, F, G, M and N, at 50% by Plan K and 75% by Plan L, and not at all by Plans A and B.
• No drugs, no long-term care. Medigap plans sold after 2005 do not include drug coverage. Medigap generally does not cover long-term care in a nursing home, vision or dental care, hearing aids or eyeglasses. See does Medicare cover long-term care.
• One person per policy. If you and your spouse both want Medigap, you each buy your own policy.
• How premiums rise. Each Medigap policy is priced one of three ways. Community-rated policies generally charge everyone the same premium regardless of age. Issue-age-rated policies base the premium on your age when you buy. Attained-age-rated policies rise as you get older, so they may be cheapest at first and can become the most expensive later. Ask which method a policy uses before you compare prices.

Questions to answer before you choose

There is no single answer, but these questions sort out most of the trade-off:

1. Your doctors. Are the doctors and hospitals you use in a plan’s network, and will they stay in it? With Original Medicare, the question is only whether they take Medicare.
2. Your drugs. Does the plan, or the separate Part D plan, cover your drugs, and at what cost?
3. Travel. Do you spend part of the year in another state or abroad? Medicare Advantage plans have service areas and networks, and emergency cover abroad varies.
4. A bad year. Could your budget absorb a year at the plan’s out-of-pocket limit? Could it absorb a steady Medigap premium every year?
5. Later. If your health changes, would you want the option to move to Original Medicare with Medigap? Outside your 6-month window, that option may not be there.
6. Income. Higher earners pay an extra charge, called IRMAA, on the Part B premium and on drug coverage, including a Medicare Advantage plan’s drug coverage. See IRMAA brackets.

If you are already in a plan, read its Annual Notice of Change each fall before December 7.

Where to get free help

• Your State Health Insurance Assistance Program (SHIP). SHIPs get federal money to give free, personalized Medicare counseling, including on choosing a health plan and buying a Medigap policy. They are not connected to any insurance company or plan. Find yours at shiphelp.org.
• 1-800-MEDICARE (1-800-633-4227, TTY 1-877-486-2048), and the plan finder at medicare.gov.
• Your State Insurance Department, for the Medigap rules your state adds.

Medicare’s handbook notes that a trusted agent or broker may also be able to help. Under Medicare’s marketing rules, an agent, broker or marketing company that sells for more than one Medicare Advantage company, but not for all of them in your area, has to tell you “We do not offer every plan available in your area.” It is fair to ask any agent which insurers they represent and how they are paid.

About this guide

Written by the Diversify Guy editorial desk. Diversify Guy is a pen name. It is the byline of our editorial team, not a single individual. We do not publish personal trading records or claim to be your adviser. We tell you where every figure came from so you can check it yourself. How we work and how we get paid.

This guide explains federal Medicare rules; states can add their own rules for Medigap. It is not personalized insurance, tax, legal or financial advice, and we do not recommend any plan, insurer or agent. Diversify Guy earns affiliate commissions and advertising fees from companies featured elsewhere on the site. This page carries no ads and no affiliate links.

Sources and check dates

All sources checked on November 4, 2026.

• Medicare.gov, Compare Original Medicare and Medicare Advantage: https://www.medicare.gov/basics/get-started-with-medicare/get-more-coverage/your-coverage-options/compare-original-medicare-medicare-advantage
• Choosing a Medigap Policy (CMS publication 02110, 2026): https://www.medicare.gov/publications/02110-choosing-a-medigap-policy.pdf
• Medicare & You 2027, the official handbook (Medigap and Medicare Advantage rules, Plan K, L and N figures, enrollment periods, Annual Notice of Change, SHIP): https://www.medicare.gov/publications/10050-medicare-and-you.pdf
• Medicare.gov, Compare Medigap plan benefits (benefit table): https://www.medicare.gov/health-drug-plans/medigap/basics/compare-plan-benefits
• CMS, Final CY 2027 Part C Bid Review Memorandum (HPMS memo of April 22, 2026), Table 3 (2027 out-of-pocket limits) and the rule for Medical Savings Account plans; CMS posts it in the zip file on its HPMS memos page for April 20 to 24, 2026: https://www.cms.gov/about-cms/information-systems/hpms/hpms-memos-archive-weekly/hpms-memos-wk-4-april-20-24
• CMS, Final CY 2026 Part C Bid Review Memorandum (HPMS memo of April 16, 2025), Table 3 (2026 out-of-pocket limits); CMS posts it in the zip file on its HPMS memos page for April 14 to 18, 2025: https://www.cms.gov/about-cms/information-systems/hpms/hpms-memos-archive-weekly/hpms-memos-wk-3-april-14-18
• 42 CFR 422.100(f)(4), the regulation behind the out-of-pocket limits: https://www.ecfr.gov/current/title-42/section-422.100
• 42 CFR 422.2267(e)(41) and 422.2274, Medicare’s marketing rules for agents, brokers and other third-party marketers: https://www.ecfr.gov/current/title-42/section-422.2267 and https://www.ecfr.gov/current/title-42/section-422.2274
• CMS, CY 2027 Rate Announcement (2027 Part D deductible and out-of-pocket threshold): https://www.cms.gov/files/document/2027-announcement.pdf
• CMS, 2026 Medicare Parts A and B premiums and deductibles: https://www.cms.gov/newsroom/fact-sheets/2026-medicare-parts-b-premiums-deductibles
• CMS address for the 2027 Parts A and B fact sheet, which returned “Page Not Found” on November 4, 2026: https://www.cms.gov/newsroom/fact-sheets/2027-medicare-parts-b-premiums-deductibles
• CMS, Medigap high deductible options F, G and J for 2027: https://www.cms.gov/files/document/cy-2027-medigap-high-deductible-options-fjg.pdf-0
• 42 U.S.C. 1395ss (Social Security Act section 1882), Medigap open enrollment, 2024 edition: https://www.govinfo.gov/content/pkg/USCODE-2024-title42/html/USCODE-2024-title42-chap7-subchapXVIII-partE-sec1395ss.htm