Quick answer: Medigap and Medicare Advantage are not two versions of the same product. Medigap is a supplement that sits on top of Original Medicare and pays much of what Medicare leaves behind, usually for a higher monthly premium but with few bills later and any doctor that takes Medicare. Medicare Advantage replaces Original Medicare with a private plan that bundles coverage, often with a low premium, but with networks, prior authorization and copays up to a yearly cap. You can only have one route at a time.
Choosing between Medicare Advantage and Medigap is the biggest coverage decision most people make at 65, and it is one many revisit every fall. Advertising tends to focus on extras and $0 premiums, while the real differences sit in networks, rules for approval of care, out-of-pocket exposure and what happens if you want to switch later.
This guide sets the two routes side by side. It explains how each one works, compares costs and access, walks through the timing rules that make Medigap hard to buy later in most states, and offers a step-by-step way to decide. For the wider picture, including eligibility and enrollment windows, see our Medicare guide. If the lettered parts are still new to you, start with Medicare Parts A, B, C and D explained.
Facts below come from Medicare.gov and CMS, checked October 2026. This is general information, not a recommendation of any plan or insurer.
How Each Route Works
The simplest way to see the difference is to look at who pays your claims.
Original Medicare with Medigap
With Original Medicare, the federal government pays your Part A and Part B claims directly. You then pay your share: deductibles, 20% coinsurance for most Part B services and hospital costs after certain limits. Original Medicare has no yearly cap on that share.
A Medigap policy, also called Medicare Supplement Insurance, is sold by private insurers and pays some or all of those leftover costs. Medicare pays first, then Medigap pays its part. Medigap policies sold today do not include prescription drug coverage, so people on this route usually add a separate Part D drug plan.
Medicare Advantage
Medicare Advantage (Part C) plans are offered by private insurers approved by Medicare. When you join one, the plan becomes the way you get your Part A and Part B benefits, and most plans include Part D drug coverage too. The plan must cover the services Original Medicare covers, though it sets its own copays, coinsurance, networks and rules. Medicare Advantage plans must also set a yearly limit on what you pay out of pocket for covered in-network services.
You cannot combine them
A Medigap policy does not work with Medicare Advantage. Medicare.gov notes that it is illegal for anyone to sell you a Medigap policy if they know you are in a Medicare Advantage plan, unless you are switching back to Original Medicare. Pick one route, then review it each year.
Side-by-Side Comparison
This table summarizes the main differences. Details vary by plan, state and insurer.
| Feature | Original Medicare + Medigap + Part D | Medicare Advantage |
|---|---|---|
| Doctors and hospitals | Any provider in the U.S. that accepts Medicare | Plan network; HMOs usually cover only in-network care except emergencies, PPOs pay less for out-of-network care |
| Referrals | Not required | Often required in HMOs |
| Prior authorization | Rare under Original Medicare | Common for many services |
| Monthly premiums | Part B premium + Medigap premium + Part D premium | Part B premium + plan premium (many plans have low or $0 plan premiums) |
| Costs when you use care | Low to none, depending on the Medigap plan | Copays and coinsurance, up to the plan’s yearly out-of-pocket limit |
| Drug coverage | Separate Part D plan | Usually included |
| Extras such as dental or vision | Not included; buy separately | Often included, with limits |
| Foreign travel emergencies | Several Medigap plans pay 80% up to plan limits | Varies by plan |
| Ease of switching later | Medigap may require health questions after your first window | You can change plans each fall |
Reading the table carefully
The table shows trade-offs rather than a winner. Medigap buys predictability and freedom of choice for a higher fixed monthly cost. Medicare Advantage often lowers that fixed cost but shifts some cost to the moment you use care and adds rules about where and how you get it.
Costs: Premiums Versus Bills
Comparing costs means looking at two kinds of spending: what you pay every month no matter what, and what you pay when you need care. Our explainer on deductibles, copays, coinsurance and out-of-pocket maximums defines each term.
Medigap costs
Everyone on this route pays the Part B premium, which is $202.90 a month in 2026 for most people, plus a Medigap premium and a Part D premium. Medigap premiums vary by insurer, plan letter, age, location and the way the company prices its policies. Medicare.gov describes three pricing methods: community-rated (same price regardless of age), issue-age-rated (based on your age when you buy) and attained-age-rated (based on your current age, so it rises as you get older).
In return, costs at the doctor or hospital can be very low. According to Medicare.gov’s Medigap plan comparison chart, Plan G covers everything in the chart except the Part B deductible ($283 in 2026), and Plan N covers the Part B coinsurance except for copays of up to $20 for some office visits and up to $50 for emergency room visits that do not lead to admission.
Medicare Advantage costs
Medicare Advantage members also pay the Part B premium. Many plans charge little or nothing extra each month, and a few reduce the Part B premium. Costs appear as copays, coinsurance and deductibles when you use care, until you reach the plan’s out-of-pocket limit for the year. After that, the plan pays 100% of covered in-network services for the rest of the year.
A fair way to compare
Estimate a “good year,” with only routine visits, and a “bad year,” with a hospital stay, surgery or ongoing treatment. Add up premiums plus expected bills for each scenario. Medicare Advantage may cost less in a good year, while Medigap’s higher premiums often look different in a bad year. Including drug costs from the Medicare Plan Finder makes the comparison complete.
Access to Care: Networks, Referrals and Approvals
Cost matters, but access to the doctors and treatments you want often decides the question.
Networks. Original Medicare works with any provider that accepts Medicare, almost anywhere in the United States. Medicare Advantage plans contract with networks. HMO plans generally cover only in-network care except for emergencies and urgent care. PPO plans cover out-of-network care at a higher cost. Networks can change from year to year, and a doctor can leave a network during the year.
Referrals. Many HMO plans require a referral from your primary care doctor before you see a specialist. Original Medicare does not.
Prior authorization. Medicare Advantage plans commonly require approval before covering certain services, procedures, drugs or stays. Original Medicare uses prior authorization for only a small set of services. If a request is denied, you have appeal rights explained in your plan’s Evidence of Coverage.
Travel and second homes. People who travel often or spend part of the year in another state usually find Original Medicare easier because it is accepted nationwide. Some PPO plans offer broader coverage, but rules vary.
Extras. Many Medicare Advantage plans include some dental, vision, hearing or fitness benefits. These can be valuable, though coverage limits, networks and annual maximums vary widely, so check the plan’s details before choosing based on extras alone.
The Medigap Timing Trap
Timing is where many people get caught, and it is the main reason this decision matters so much at 65.
Medigap Open Enrollment
Your Medigap Open Enrollment Period is a one-time, six-month window that starts the first month you are 65 or older and enrolled in Part B. During that window, Medicare.gov says an insurer cannot refuse to sell you any Medigap policy it offers, charge you more because of past or present health problems, or make you wait for coverage of a pre-existing condition, with limited exceptions. Our guide to when to sign up for Medicare explains how this window lines up with your first Part B enrollment.
After the window closes
In most states, insurers can use medical underwriting once your Medigap window has passed. That means they can ask health questions and may refuse coverage or charge more. A person who picks Medicare Advantage at 65 and later wants to move to Original Medicare with Medigap may find that switch difficult if their health has changed.
Guaranteed issue rights
Federal law gives guaranteed issue rights in specific situations, such as when a Medicare Advantage plan leaves your area or stops serving Medicare. There is also a “trial right”: if you joined a Medicare Advantage plan when first eligible at 65 and want to leave within the first year, you can generally return to Original Medicare and buy a Medigap policy without underwriting. People who dropped a Medigap policy to join Medicare Advantage for the first time may be able to return to their old policy within 12 months if it is still sold.
State protections
Some states give broader rights. New York and Connecticut, for example, allow people to buy Medigap year-round without medical underwriting, and other states have annual windows or other rules. Your state insurance department, or your State Health Insurance Assistance Program (SHIP), can explain the rules where you live.
Who Each Route Tends to Suit
Every situation is different, but common patterns help frame the decision.
Original Medicare with Medigap may fit if you
- Want to see any doctor or hospital that accepts Medicare without referrals
- Travel often in the U.S. or live in more than one state during the year
- Prefer predictable costs and few bills, even with higher premiums
- Have health conditions that need specialists or frequent care
- Want to avoid prior authorization for most services
- Are within your Medigap Open Enrollment Period and want to keep options open later
Medicare Advantage may fit if you
- Want lower monthly premiums and are comfortable paying copays as you use care
- Are happy with the doctors and hospitals in a plan’s network
- Value bundled drug coverage and extras like dental or vision benefits
- Prefer one plan, one card and one company to deal with
- Accept that some care will need referrals or prior approval
When the answer is less clear
People with expensive prescriptions, chronic conditions or a strong preference for particular doctors should look closely at both routes. Comparing total costs and checking whether specific doctors, hospitals and drugs are covered in each option usually makes the choice clearer.
A Step-by-Step Way to Decide
These steps work for first-time enrollees and for anyone reviewing coverage during the Annual Enrollment Period, which runs from October 15 to December 7 each year.
- List your doctors, hospitals and prescriptions. Include doses and pharmacies.
- Check networks. For each Medicare Advantage plan, confirm your doctors and hospitals are in network for next year.
- Compare drug costs. Use the Medicare Plan Finder on Medicare.gov to estimate yearly drug costs for Part D plans and Advantage plans.
- Estimate good-year and bad-year costs. Add premiums, deductibles, copays and the out-of-pocket maximum for each option.
- Check Medigap prices. Ask several insurers for quotes on the same plan letter, and ask how each prices its policies.
- Consider your future. Think about health changes, travel plans and whether you might want to switch routes later, given the Medigap underwriting rules in your state.
- Get free help. A SHIP counselor can review your options at no cost.
- Read the documents. Before enrolling, read the plan’s Summary of Benefits and Evidence of Coverage, or the Medigap policy outline.
People already covered by another policy, such as retiree benefits or a spouse’s plan, should also ask how that coverage works with each option. Our article on having two health insurance policies explains how primary and secondary coverage generally work.
FAQ
Frequently Asked Questions
Can I have both Medigap and Medicare Advantage?
No. Medigap works only with Original Medicare. If you join a Medicare Advantage plan, a Medigap policy would not pay for your care, and insurers may not sell you one while you are in an Advantage plan unless you are switching back.
Which is cheaper, Medigap or Medicare Advantage?
Medicare Advantage often has lower monthly premiums, while Medigap usually leads to lower bills when you use care. Which one costs less overall depends on your health, the plans available and how much care you need in a year.
Can I switch from Medicare Advantage to Medigap later?
You can return to Original Medicare during certain enrollment periods, but in most states a Medigap insurer can use medical underwriting after your Medigap Open Enrollment Period, unless you have a guaranteed issue right or live in a state with broader protections.
Does Medigap include drug coverage?
Medigap policies sold today do not include prescription drug coverage. People with Original Medicare and Medigap usually join a separate Part D drug plan.
Do Medicare Advantage plans cover dental and vision?
Many plans offer some dental, vision or hearing benefits, but coverage levels, networks and yearly limits vary. Check the plan’s Evidence of Coverage for details. N: This article is general information only and is not insurance or legal advice. Pro Insurance Info does not sell Medicare plans. Confirm details with Medicare.gov, 1-800-MEDICARE, your state insurance department or your State Health Insurance Assistance Program.
