Medigap, also called Medicare Supplement Insurance, is optional private coverage designed to help close those gaps. It doesn't replace your Medicare benefits. It works alongside them.
This guide covers how Medigap works, which plans exist, how it stacks up against Medicare Advantage, when to enroll, and how to pick a policy that fits your health needs and budget.
Key Takeaways
- Medigap works with Original Medicare Parts A and B; it generally cannot pair with Medicare Advantage.
- Plan benefits are standardized by letter in most states, but premiums and pricing methods vary widely by insurer.
- The six-month Open Enrollment Period at 65 (while on Part B) is usually your best path to guaranteed Medigap coverage.
- Standard Medigap policies omit drugs, dental, vision, and hearing aids, so plan on separate coverage for those.
What Is Medigap Insurance?
Medigap is private insurance sold by companies like Aetna, Cigna, and others. It covers costs that Original Medicare (Part A hospital and Part B medical) doesn't fully pay. Think deductibles, coinsurance, and copayments that pile up after a hospital stay or a string of specialist visits.
You need both Part A and Part B before an insurer will sell you a Medigap policy. Here's a detail people often miss: buying Medigap doesn't lower or replace your Part B premium. You keep paying that, plus a separate premium to your Medigap insurer.
What Medigap can help with:
- Part A hospital coinsurance and deductible
- Part B coinsurance or copayments
- Skilled nursing facility coinsurance
- Hospice coinsurance
- Blood costs (first three pints)
- Foreign travel emergency care, depending on the plan
Who Typically Considers Medigap
Medigap appeals to people who want:
- Predictable monthly costs instead of surprise bills
- Access to any doctor or hospital that accepts Medicare, nationwide
- Coverage that travels with them, useful for snowbirds splitting time between Florida and points north
- Fewer referrals and network restrictions than a managed-care plan
Medigap is not the same as Medicare Advantage. Medigap supplements Original Medicare's cost-sharing. Medicare Advantage replaces Original Medicare with a private plan that delivers your Part A and Part B benefits, often bundled with Part D. More on that difference shortly.
What Does Medigap Cover, and What Plans Are Available?
Medigap plans are identified by letters: A, B, D, G, K, L, M, N, and a couple of others depending on your state. In most states, a Plan G from one insurer covers exactly the same core benefits as a Plan G from another. What changes is the premium, the insurer's service, and how rates trend over time.
Two plans get most of the attention:
- Plan G covers everything except the Part B deductible, making it the most comprehensive option available to people newly eligible for Medicare.
- Plan N costs less but requires small copays (up to $20 for some office visits and $50 for an ER visit that doesn't lead to admission) and skips Part B excess charges.
Here's a simplified look at what a few common plans cover:
| Benefit | Plan G | Plan N | Plan K |
|---|---|---|---|
| Part A hospital coinsurance | 100% | 100% | 100% |
| Part B coinsurance | 100% | 100%* | 50% |
| Skilled nursing facility coinsurance | 100% | 100% | 50% |
| Part B deductible | Not covered | Not covered | Not covered |
| Out-of-pocket limit (2026) | None | None | $8,000 |
*Plan N may require small copays for office and ER visits.
Full details for every letter, plus state-specific exceptions, are on Medicare.gov's plan comparison chart. Check it before you apply, since rules shift year to year.
Plans C and F: Who Can Still Buy Them
If you became eligible for Medicare on or after January 1, 2020, you can't buy Plan C or Plan F. Both cover the Part B deductible, which federal law no longer allows for newly eligible beneficiaries. If you were eligible before that date, you may still purchase or keep one of these plans where it's sold.
What Medigap Won't Cover
Don't expect a Medigap policy to pay for:
- Prescription drugs (a separate Part D plan handles that)
- Routine dental, vision, or hearing aids
- Long-term custodial care
- Private-duty nursing
That's why many beneficiaries pair a Medigap plan, often Plan G or Plan N, with a standalone Part D prescription drug plan. Checking your medication list against a Part D formulary is a separate step Medigap doesn't handle.
Medigap vs. Medicare Advantage: Which May Fit Your Needs?
Both routes get you more complete Medicare coverage, but they work very differently.
Medigap pairs with Original Medicare. You keep Parts A and B exactly as they are, and your Medigap policy picks up specified cost-sharing. Medicare Advantage (Part C) replaces that setup. A private insurer delivers your Part A and Part B benefits, often with Part D and extras like dental or vision bundled in.
Provider access is often the deciding factor:
- Medigap: see any provider nationwide who accepts Medicare, generally no referrals needed
- Medicare Advantage: often limited to a network or service area, with referrals required for HMO-style plans
Cost patterns differ too, and neither option wins outright:
- Medigap means a separate monthly premium plus your Part B premium, but predictable cost-sharing once you're covered
- Medicare Advantage often has a lower or $0 premium, with per-service copays and coinsurance up to the plan’s annual out-of-pocket limit
Medicare Advantage plans sometimes include dental, vision, and hearing benefits Medigap doesn’t cover. Medigap’s trade-off is different: Original Medicare has no annual out-of-pocket cap on its own, so without a supplement, frequent hospital stays or specialist care can push costs up with no ceiling.
A Quick Decision Framework
Ask yourself:
- Do I want to keep my current doctors, including specialists outside my home state?
- Am I comfortable with network rules and referrals, or do I want to skip that entirely?
- How often do I expect to need care, and can I handle unpredictable copays?
- Do I split time between states or travel frequently?
- What matters more: a lower monthly premium or fewer cost surprises later?
Neither Medigap nor Medicare Advantage is right for everyone. A retiree who travels six months a year and wants zero network hassle often leans toward Medigap plus a Part D plan.
Someone on a tighter fixed income who mostly sees local providers might prefer Medicare Advantage’s lower premium and built-in extras. Match the choice to how you use care and how much cost variability you can live with.
When Can You Enroll in Medigap?
Timing matters more with Medigap than almost any other Medicare decision.
The Medigap Open Enrollment Period
Your best window is a one-time, six-month period starting the first month you're both 65 or older and enrolled in Part B. During this stretch, insurers must sell you any Medigap policy available in your state at the standard rate, regardless of health conditions. Miss it, and you may face medical underwriting later.
This window is not the same as Medicare's Annual Enrollment Period (October 15–December 7), which covers switching Medicare Advantage or Part D plans. AEP does not restart your Medigap enrollment protections — a common point of confusion.
Guaranteed Issue Rights
Outside your initial window, you may still qualify for guaranteed issue rights if:
- Your Medicare Advantage plan leaves Medicare or exits your service area
- You move outside your Advantage plan's coverage area
- You lose employer or union coverage that paid after Medicare, including qualifying COBRA or retiree coverage
These rights typically require applying within 63 days of the coverage ending, and the specific plan letters available may be limited.
Applying Outside Protected Periods
If you apply without a protected right, insurers can:
- Ask health questions and medically underwrite your application
- Charge higher premiums based on health status
- Deny coverage entirely, where state law permits
Under-65 enrollment follows different rules. For people with Medicare due to disability, requirements vary significantly by state. Some states require insurers to offer Medigap to this group; others don't. Your State Health Insurance Assistance Program (SHIP) or state insurance department can clarify what applies where you live.
If you're in Florida, Georgia, North Carolina, Nevada, or South Carolina, Wareheim Medicare Advisors can help you map Open Enrollment and guaranteed-issue deadlines, since missing a protected window can mean higher premiums for years.
How Much Does Medigap Cost, and How Do You Choose a Plan?
Medigap premiums vary more than people expect. Two insurers selling identical Plan G benefits can charge noticeably different monthly rates.
What Drives Your Premium
- Plan letter — richer coverage like Plan G typically costs more than leaner options like Plan K
- Age and location — rates vary by where you live and how old you are
- Tobacco use — some insurers charge more where state rules allow it
- Household discounts — some insurers reduce rates when a spouse also enrolls
- Pricing method — community, issue-age, or attained-age rating shapes long-term cost
- Medical underwriting — may apply if you enroll outside a protected window
Three Pricing Methods, Explained Simply
| Pricing method | How it works | Long-term effect |
|---|---|---|
| Community-rated | Same price for everyone regardless of age | Won't rise due to age, but can rise for other reasons |
| Issue-age-rated | Price locked in based on your age when you buy | Cheaper if you buy young; no age-based increases later |
| Attained-age-rated | Price based on your current age each year | Often cheapest at first, but rises steadily as you age |
A low starting premium on an attained-age-rated policy can look attractive at 65 and become the priciest option by 80. Don't shop on first-year price alone — ask how the insurer's rates have trended historically.
A Practical Comparison Checklist
Before you choose, run through this checklist:
- Confirm your regular doctors accept Medicare (Medigap doesn't use networks)
- Estimate your expected healthcare use for the coming year
- List your prescriptions separately and price them against Part D plans
- Factor in travel habits if you split time between states
- Set a monthly premium you can sustain long-term, not just this year
- Check whether you currently qualify for guaranteed issue protections
Read the actual policy documents too. Exclusions, discount rules, premium-increase history, and what happens if you cancel or switch later matter more than the marketing brochure.
Comparing quotes across insurers and pricing structures takes time, which is why many people work with a licensed agent.
Wareheim Medicare Advisors offers no-cost, personalized Medicare brokerage assistance and annual plan reviews for clients across Florida, Georgia, North Carolina, Nevada, and South Carolina. The practice compares coverage against your health needs, budget, and preferred providers rather than pushing a single carrier.
Frequently Asked Questions
Is it better to have a Medigap plan or a Medicare Advantage plan?
It depends on your provider preferences, budget, prescription needs, and travel habits. Medigap fits people who want nationwide doctor access and predictable costs. Medicare Advantage may fit those who want lower premiums and bundled extras.
Is a Medigap plan really necessary?
Medigap is optional, not required. Consider it if you want help with Original Medicare cost-sharing and prefer predictable expenses. Affordability and risk tolerance should guide the decision.
What is the most popular Medigap plan?
As of 2024, Plan G led Medigap enrollment at 43%, with Plan F next at 33%, per AHIP’s 2026 Medicare Supplement report. Popularity alone doesn’t mean it’s the right fit for you.
What percentage of Medicare beneficiaries have Medigap?
KFF's analysis found Medigap covered 20% of all Medicare beneficiaries and 43% of those in traditional Medicare as of 2023. These two percentages measure different populations, so it's easy to mix them up.
When is the best time to enroll in Medigap?
Your strongest position is the six-month Medigap Open Enrollment Period that starts once you're 65 and enrolled in Part B. Applying then generally avoids medical underwriting; other qualifying life events can create separate enrollment rights.
Does Medigap cover prescription drugs, dental, or vision care?
No. Standard Medigap policies exclude prescription drugs, routine dental, vision, and hearing aids. Most beneficiaries pair Medigap with a standalone Part D plan and separate dental or vision coverage if needed.
