Quick Answer
Original Medicare (Parts A and B) covers a wide range of medical services, but it leaves significant gaps, including a 20% coinsurance on all Part B services with no out-of-pocket maximum, hospital deductibles, and no coverage for dental, vision, or hearing. Without supplemental coverage, a serious illness or hospitalization can result in thousands of dollars in out-of-pocket costs. Most Medicare beneficiaries benefit from some form of supplemental coverage, either a Medigap plan, a Medicare Advantage plan, or Medicaid for those who qualify.
Coverage Comparison by Plan Type
| Plan Type | Coverage | Notes |
|---|---|---|
| Original Medicare Only | Gaps Exist | No out-of-pocket maximum. You pay 20% of all Part B costs indefinitely. Hospital deductibles apply. No dental, vision, or hearing. |
| Original Medicare + Medigap | Most Comprehensive | Medigap fills most or all of Original Medicare's cost-sharing gaps. Predictable costs. Freedom to see any Medicare-accepting provider nationwide. |
| Medicare Advantage (Part C) | Comprehensive + Extras | Replaces Original Medicare with an all-in-one plan. Includes out-of-pocket maximum. Often includes dental, vision, hearing, and other extras. Network restrictions apply. |
| Medicaid (if eligible) | Covers Most Gaps | For low-income beneficiaries, Medicaid can cover most or all of Medicare's cost-sharing. Eligibility based on income and assets. |
Understanding Your Coverage Options
What Original Medicare Does not Cover
Original Medicare (Parts A and B) covers most medically necessary hospital and medical services, but it has several significant gaps that can lead to large out-of-pocket costs. The most important gap is the lack of an out-of-pocket maximum. Unlike private insurance, Original Medicare has no cap on what you can owe in a given year. If you have a serious illness requiring extended hospital stays and ongoing treatment, your costs can accumulate without limit.
Part B charges a 20% coinsurance on all covered services after the annual deductible ($257 in 2026). There is no cap on this 20%. A $100,000 surgery, for example, would leave you responsible for $20,000 in coinsurance under Original Medicare alone. Part A has its own deductible ($1,676 per benefit period in 2026) and daily coinsurance for extended hospital stays.
What It Covers
- Part A deductible: $1,676 per benefit period in 2026
- Part B deductible: $257 per year in 2026
- Part B coinsurance: 20% of all covered services (no annual cap)
- Hospital coinsurance: $419/day for days 61–90; $838/day for lifetime reserve days
- Skilled nursing facility coinsurance: $209.50/day for days 21–100
- No coverage for dental, vision, hearing, or routine foot care
- No coverage for most prescription drugs (requires separate Part D plan)
- No coverage for long-term care or custodial care
What It Doesn't Cover
- Original Medicare does not cover routine dental, vision, or hearing exams or treatment
- No prescription drug coverage without a separate Part D plan
- No long-term care (nursing home) coverage beyond 100 days in a skilled nursing facility
$ Example: A $50,000 hospitalization + $100,000 in Part B services = $20,000+ in out-of-pocket costs under Original Medicare alone, with no cap.
No Out-of-Pocket Maximum is a Major Risk
The single biggest financial risk of Original Medicare alone is the absence of an out-of-pocket maximum. A serious illness such as cancer, heart disease, or a major surgery can result in tens of thousands of dollars in 20% coinsurance charges. Supplemental coverage eliminates or caps this risk.
Option 1: Original Medicare ++ Medigap
A Medicare Supplement (Medigap) plan works alongside Original Medicare to cover most or all of the cost-sharing gaps. The most popular option is Plan G, which covers the Part A deductible, all Part B coinsurance (after the Part B deductible), skilled nursing facility coinsurance, and foreign travel emergency coverage. With Plan G, your only predictable out-of-pocket cost is the annual Part B deductible ($257 in 2026).
Medigap plans are sold by private insurance companies but are standardized by the federal government. Plan G covers the same benefits regardless of which company you buy it from. Premiums vary by carrier, age, location, and pricing method. In 2026, Plan G premiums typically range from $100 to $250/month depending on your age and location. You also need a separate Part D plan for prescription drugs.
What It Covers
- Plan G: covers Part A deductible, all Part B coinsurance, SNF coinsurance, foreign travel emergency
- Plan N: covers most gaps with small copays ($20 at doctor visits, $50 at ER); lower premium than Plan G
- Freedom to see any Medicare-accepting provider nationwide with no network restrictions
- Predictable monthly premium with minimal unexpected costs
- No prior authorization requirements for Medicare-covered services
What It Doesn't Cover
- Medigap does not cover dental, vision, hearing, or long-term care
- Medigap does not include prescription drug coverage; you need a separate Part D plan
- Medigap premiums increase over time (especially with attained-age pricing)
$ Plan G premiums: typically $100–$250/month at age 65, depending on location and carrier. Add $20–$50/month for a Part D drug plan. Total supplemental cost: ~$120–$300/month for near-complete coverage.
Plan G is the Most Popular Choice for New Enrollees
Plan G is the most comprehensive Medigap plan available to new enrollees (Plan F is no longer available to those who became eligible after January 1, 2020). With Plan G, your only predictable out-of-pocket cost is the $257 Part B deductible. Everything else Medicare covers, Plan G covers the remainder.
Option 2: Medicare Advantage (Part C)
Medicare Advantage (Part C) is an alternative to Original Medicare + Medigap. Instead of filling gaps in Original Medicare, Medicare Advantage replaces Original Medicare entirely with a private insurance plan. All Medicare Advantage plans must cover everything Original Medicare covers, and most include prescription drug coverage (MAPD plans), plus extra benefits like dental, vision, hearing, and fitness memberships.
Medicare Advantage plans have an annual out-of-pocket maximum ($9,350 for in-network costs in 2026), which protects you from catastrophic costs. However, they use provider networks (HMO or PPO), require referrals in some cases, and may require prior authorization for certain services. Many plans have $0 premiums beyond the Part B premium, making them attractive for cost-conscious beneficiaries.
What It Covers
- All Medicare Part A and Part B benefits
- Prescription drug coverage (most plans)
- Annual out-of-pocket maximum ($9,350 in-network in 2026)
- Extra benefits: dental, vision, hearing, fitness, transportation (varies by plan)
- Often $0 monthly premium beyond the Part B premium
What It Doesn't Cover
- Network restrictions: you must use in-network providers for the lowest costs
- Prior authorization may be required for some services
- Out-of-network costs can be high in HMO plans
- Plans change annually; benefits and networks can shift each year
$ Many Medicare Advantage plans have $0 monthly premiums. You still pay the Part B premium ($185/month in 2026). Out-of-pocket costs depend on how much care you use and whether you stay in-network.
Medicare Advantage vs. Medigap: The Core Trade-Off
Medicare Advantage typically offers lower monthly premiums and extra benefits (dental, vision, hearing) but restricts you to a network and may require prior authorization. Medigap offers more predictable costs and complete freedom to see any Medicare provider nationwide, but has higher monthly premiums and no extra benefits.
Out-of-Pocket Cost Comparison: Original Medicare vs. Supplemental Options (2026)
| Coverage Type | Monthly Premium | Out-of-Pocket Max | Doctor Visit Cost | Hospital Stay Cost |
|---|---|---|---|---|
| Original Medicare Only | $185 (Part B only) | None | 20% of approved amount | $1,676 deductible + daily coinsurance |
| Original Medicare + Plan G | $185 + $100–$250 (Medigap) | ~$257/year (Part B deductible) | $0 after Part B deductible | $0 (Plan G covers Part A deductible) |
| Original Medicare + Plan N | $185 + $80–$180 (Medigap) | ~$257 + copays | $20 copay | $0 (Plan N covers Part A deductible) |
| Medicare Advantage (HMO) | $185 (Part B) + $0–$50 (MA) | $9,350 in-network (2026) | $0–$30 copay (in-network) | $0–$350/day (in-network, varies) |
| Medicare Advantage (PPO) | $185 (Part B) + $0–$100 (MA) | $9,350 in-network (2026) | $0–$50 copay (in-network) | $0–$500/day (in-network, varies) |
✦ Who May not Need a Supplement
Dual-Eligible Beneficiaries (Medicare ++ Medicaid)
If you qualify for both Medicare and Medicaid, Medicaid typically covers most or all of Medicare's cost-sharing, including deductibles, coinsurance, and copays. You may not need a separate Medigap plan or Medicare Advantage plan. Contact your state Medicaid office to understand what is covered in your state.
Medicaid can cover Medicare's gaps for low-income beneficiaries. A separate Medigap plan may not be needed
Veterans with VA Benefits
Veterans who receive healthcare through the VA may have most of their medical needs covered without a Medigap plan. However, VA coverage is limited to VA facilities and VA-approved providers. A Medigap or Medicare Advantage plan can provide coverage when VA care is not accessible or for non-VA providers.
VA benefits cover care at VA facilities. A supplement may still be useful for non-VA providers
Healthy Beneficiaries with Limited Budgets
If you are in excellent health, rarely use medical services, and have significant savings to cover unexpected costs, you might choose to go without supplemental coverage, especially if you enroll in Original Medicare only and self-insure against the 20% coinsurance risk. However, this strategy carries significant financial risk if a serious illness occurs. Most financial advisors recommend at least a Medicare Advantage plan for its out-of-pocket maximum protection.
Going without supplemental coverage is a high-risk strategy. Even healthy people can face sudden, expensive medical events
✦ Frequently Asked Questions
David Haass
AuthorDavid Haass is a Medicare content writer at MedicareFAQ with extensive experience explaining Medicare benefits, enrollment, and coverage options to beneficiaries.
Ashlee Zareczny
ReviewerAshlee Zareczny is the Compliance and Editorial Manager at MedicareFAQ, ensuring all Medicare content is accurate, up-to-date, and compliant with CMS guidelines.