What is Medicare Supplement Insurance?
Medicare Supplement Insurance, commonly called Medigap, is private health insurance designed specifically to fill the "gaps" in Original Medicare (Parts A and B) coverage. These gaps include deductibles, coinsurance, and copayments that beneficiaries would otherwise pay out-of-pocket for Medicare-covered services.
According to the Centers for Medicare & Medicaid Services, over 14 million Medicare beneficiaries have Medigap policies, making it one of the most popular ways to supplement Original Medicare coverage.
This comprehensive guide explains everything you need to know about Medicare Supplement insurance in 2025, including standardized plans, costs, enrollment rules, and how to choose the right coverage for your needs.
How Medicare Supplement Insurance Works
The Partnership with Original Medicare
Medigap works in conjunction with Original Medicare, not as a replacement. Here's how the process works:
- You receive care: Visit any doctor or hospital that accepts Medicare
- Original Medicare pays first: Medicare Parts A and B pay their share of approved charges
- Medigap pays second: Your Medigap policy automatically pays some or all of the remaining costs
- You pay the difference (if any): Depending on your plan, you may owe little to nothing
According to Medicare.gov, most Medigap policies are "guaranteed renewable," meaning the insurance company can't cancel your policy as long as you pay premiums, regardless of health issues that develop.
What Medicare Supplement Covers
Medigap policies help pay for:
- Part A coinsurance and hospital costs: Coverage for up to 365 additional days after Medicare benefits end
- Part B coinsurance or copayment: The 20% coinsurance you'd otherwise pay for most Medicare-covered services
- First three pints of blood: Blood needed for medical procedures
- Part A hospice coinsurance or copayment: Cost-sharing for hospice care
- Skilled nursing facility coinsurance: Daily coinsurance for days 21-100 of skilled nursing care
- Part A deductible: The $1,632 deductible per benefit period (2025)
- Part B deductible: The $240 annual deductible (2025) - only covered by Plans C and F
- Part B excess charges: When doctors charge more than Medicare-approved amounts (Plans F, G, and N offer this)
- Foreign travel emergency: 80% of emergency care costs when traveling abroad (most plans include this)
What Medicare Supplement Doesn't Cover
Important to understand, Medigap policies do not:
- Include prescription drug coverage (you need a separate Part D plan)
- Cover vision care, dental care, or hearing aids
- Pay for long-term care (nursing home care)
- Cover private-duty nursing
- Work with Medicare Advantage plans (you can't have both)
Standardized Medigap Plans: Understanding Your Options
Federal Standardization of Medigap Plans
One of the most important features of Medigap is standardization. The federal government requires that Medigap policies be standardized, which means:
- Every Plan G from every company offers identical benefits
- Every Plan N from every company offers identical benefits
- The only differences between carriers are price and customer service
This standardization, established by the CMS, makes comparing plans straightforward—you're comparing apples to apples.
Available Medigap Plans in 2025
There are ten standardized Medigap plans, identified by letters: A, B, C, D, F, G, K, L, M, and N. Each letter represents a different level of coverage. (Note: Plans C and F are only available to those who became eligible for Medicare before January 1, 2020.)
Most Popular Plans:
- Plan G: Most comprehensive coverage available to new beneficiaries (most popular choice)
- Plan N: Excellent coverage with slightly lower premiums
- Plan F: Comprehensive coverage for those grandfathered in (closed to new enrollees)
High-Deductible Options:
- High-Deductible Plan G: Lower premiums but $2,800 annual deductible (2025)
- High-Deductible Plan F: For those grandfathered in, $2,800 annual deductible (2025)
Cost-Sharing Plans:
- Plans K and L: Lower premiums with cost-sharing (you pay percentages of costs)
Medigap Plan Comparison Chart
Here's what each standardized plan covers (✓ = covered by plan, blank = not covered):
| Benefit | A | B | C* | D | F* | G | K | L | M | N |
|---|---|---|---|---|---|---|---|---|---|---|
| Part A coinsurance | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | 50% | 75% | ✓ | ✓ |
| Part B coinsurance | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | 50% | 75% | ✓ | ✓** |
| Part A deductible | ✓ | ✓ | ✓ | ✓ | ✓ | 50% | 75% | 50% | ✓ | |
| Part B deductible | ✓ | ✓ | ||||||||
| Part B excess charges | ✓ | ✓ | ||||||||
| Foreign travel emergency | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ |
*Plans C and F are only available to those who became Medicare eligible before January 1, 2020
**Plan N requires copays for some doctor visits and emergency room visits
Medigap Enrollment: When and How to Apply
The Medigap Open Enrollment Period
Your Medigap Open Enrollment Period is a good time to buy a Medigap policy. This period:
- Lasts for six months
- Starts the first day of the month you're 65 or older and enrolled in Medicare Part B
- Guarantees you can buy any Medigap policy sold in your state
- Protects you from medical underwriting—insurance companies can't refuse you or charge more due to health problems
- Protects you from pre-existing condition waiting periods
According to Medicare.gov, this is your strongest opportunity to enroll in Medigap because of these consumer protections.
Enrolling Outside the Open Enrollment Period
If you apply for Medigap outside your Open Enrollment Period, insurance companies in most states can:
- Use medical underwriting to decide whether to accept your application
- Charge you more due to health conditions
- Refuse to sell you a policy
- Make you wait up to six months for coverage of pre-existing conditions
This is why timing is critical when enrolling in Medigap.
Guaranteed Issue Rights
You have guaranteed issue rights (also called Medigap protections) in certain situations that allow you to buy a Medigap policy. In those situations the insurer cannot decline you or charge more because of your health. These situations include:
- You're in a Medicare Advantage Plan and your plan is leaving Medicare or stops serving your area: You can buy Plans A, B, C, F, K, or L
- You move out of your plan's service area: You can buy Plans A, B, C, F, K, or L
- Your employer group coverage is ending: You can buy any Medigap plan
- You dropped a Medigap policy to join Medicare Advantage for the first time: You can return to your old policy or buy Plans A, B, C, F, K, or L (within 12 months)
- Your Medigap company goes bankrupt: You can buy any Medigap plan
The Medicare.gov guaranteed issue guide provides comprehensive information about these special situations.
Medicare Supplement Costs and Pricing Methods
Understanding Premium Pricing Methods
Medigap insurance companies use three different pricing methods to set premiums. Understanding these methods helps you predict future costs:
1. Community-Rated (No Age Rating)
Everyone pays the same premium regardless of age. A 65-year-old and an 85-year-old pay the same amount. Premiums may increase due to inflation but not due to age.
Advantage: Predictable; your premium won't increase as you age
Disadvantage: Often higher initial premiums
2. Issue-Age Rated
Your premium is based on your age when you buy the policy. Premiums don't increase as you age, but they may increase due to inflation.
Advantage: Your premium is locked in at your enrollment age
Disadvantage: Still subject to general rate increases
3. Attained-Age Rated (Most Common)
Your premium starts low but increases as you age in addition to general rate increases. This is the most common pricing method.
Advantage: Lower premiums when you're younger
Disadvantage: Premiums increase as you age, which can be significant over time
Average Medigap Premiums in 2025
While premiums vary significantly by location, age, and insurance company, here are typical monthly premium ranges for popular plans (65-year-old):
- Plan G: $120-$250 per month
- Plan N: $95-$185 per month
- Plan F: $150-$280 per month (closed to new enrollees)
- High-Deductible Plan G: $40-$80 per month
Premiums in high-cost states like New York, California, and Florida tend to be higher, while premiums in states like Wisconsin, Minnesota, and Iowa tend to be lower.
Factors Affecting Your Premium
Several factors influence your Medigap premium:
- Age: Older applicants typically pay more (attained-age pricing)
- Location: State and ZIP code significantly affect pricing
- Gender: In some states, females pay slightly more due to longer life expectancy
- Tobacco use: Smokers often pay 15-25% more
- Household discount: Some carriers offer discounts when spouses both have policies
- Payment method: Annual or automatic payment discounts may be available
Medigap vs. Medicare Advantage: Making the Right Choice
Key Differences
| Feature | Medigap + Original Medicare | Medicare Advantage |
|---|---|---|
| Provider Choice | Any doctor/hospital that accepts Medicare | Must use plan network (HMO) or pay more (PPO) |
| Referrals | Not required | May be required (HMO plans) |
| Travel Coverage | Works nationwide; foreign travel emergency coverage | Limited outside service area except emergencies |
| Monthly Premium | Higher premiums ($120-250+ for Plan G) | Lower premiums (some $0 plans) |
| Out-of-Pocket Costs | Very predictable; minimal copays | Variable copays/coinsurance |
| Out-of-Pocket Maximum | None (but Medigap covers most costs) | Yes ($8,850 maximum for 2025) |
| Prescription Drugs | Separate Part D plan required | Usually included |
| Extra Benefits | None (dental, vision separate) | Often includes dental, vision, hearing, gym |
When Medigap Makes More Sense
Consider Original Medicare with Medigap if you:
- Want freedom to see any Medicare provider without referrals
- Travel frequently or have multiple residences (snowbirds)
- See specialists regularly
- Have complex medical needs or chronic conditions
- Prefer predictable costs over lower premiums
- Value peace of mind with comprehensive coverage
- Want to avoid network restrictions
When Medicare Advantage Makes More Sense
Consider Medicare Advantage if you:
- Want lower monthly premiums
- Prefer all-in-one coverage including drugs
- Value extra benefits like dental and vision
- Don't travel frequently outside your area
- Are comfortable with network restrictions
- Have good local network options
Read our comprehensive comparison: Medigap vs Medicare Advantage: Which is Right for You?
How to Choose the Right Medigap Plan
Step 1: Understand Your Healthcare Needs
Consider your current health status and healthcare utilization:
- How often do you visit doctors and specialists?
- Do you have chronic conditions requiring ongoing care?
- How many prescriptions do you take?
- Do you travel frequently?
- What's your annual healthcare spending?
Step 2: Decide on Plan Type
Most beneficiaries choose between three plans:
- Plan G: Strong for comprehensive coverage with predictable costs
- Plan N: Strong for lower premiums with modest cost-sharing
- High-Deductible Plan G: Strong for healthy beneficiaries wanting catastrophic coverage
Step 3: Compare Insurance Companies
Since all Plan G policies are identical in coverage, compare carriers based on:
- Premium: Monthly cost for the same coverage
- Rate increase history: How much have premiums increased annually?
- Financial stability: Check financial strength ratings (A- or higher)
- Customer service: Read reviews and check complaint ratios
- Discounts: Household, payment method, or other discounts
Step 4: Calculate Total Costs
Compare the total annual cost of each option:
Plan G Total Cost:
- Annual premiums (Medigap premium × 12)
- Plus Part B premium ($174.70/month standard 2025)
- Plus Part B deductible ($240 annual)
- Plus Part D premium (average $40-50/month)
Plan N Total Cost:
- Annual premiums (Medigap premium × 12)
- Plus Part B premium
- Plus Part B deductible
- Plus Part D premium
- Plus estimated office visit copays ($20 each × estimated visits)
- Plus estimated ER copays ($50 each, waived if admitted)
Step 5: Apply During Your Open Enrollment Period
To avoid medical underwriting, apply during your Medigap Open Enrollment Period (first six months after turning 65 and enrolling in Part B).
Common Medigap Questions and Misconceptions
Can I switch Medigap plans later?
Yes, you can switch Medigap plans at any time. However, outside your Open Enrollment Period or guaranteed issue situations, you may face medical underwriting. Insurance companies can deny coverage or charge more based on your health.
Will my Medigap policy work in other states?
Yes, Medigap policies work anywhere in the United States as long as the provider accepts Medicare. Some plans even cover emergency care during foreign travel.
Do I need both Medigap and Medicare Advantage?
No, and it's illegal for insurance companies to sell you both simultaneously. You must choose Original Medicare + Medigap OR Medicare Advantage. You cannot have both.
Does Medigap cover prescription drugs?
No, Medigap policies do not include prescription drug coverage. You need to enroll in a standalone Medicare Part D plan for drug coverage. The only exception is Plans C and F sold before 2006, which may include very limited prescription coverage.
Can my Medigap policy be cancelled?
No, as long as you pay your premiums, your Medigap policy is guaranteed renewable. The insurance company cannot cancel your policy due to health problems. This is a federal protection under the Medigap law.
What happens to my Medigap policy when I turn 65 and have employer coverage?
If you have creditable employer coverage when you turn 65, you can delay enrolling in Medicare and Medigap without penalty. Your Medigap Open Enrollment Period begins when you lose that employer coverage and enroll in Medicare Part B.
Special Considerations for Different Situations
Medigap for People Under 65 with Disabilities
If you're under 65 and have Medicare due to disability, Medigap enrollment rules vary by state. Some states require insurance companies to sell you policies, while others don't. Contact your State Health Insurance Assistance Program (SHIP) for state-specific rules.
Medigap for People with End-Stage Renal Disease (ESRD)
If you have End-Stage Renal Disease, you generally can't buy a Medigap policy unless you're also eligible for Medicare due to age (65 or older) or disability. Once you're eligible, you have the same Medigap Open Enrollment rights as other Medicare beneficiaries.
Medigap for Snowbirds and Frequent Travelers
Medigap is ideal for beneficiaries who split time between multiple states or travel frequently. Unlike Medicare Advantage plans with network restrictions, Medigap works with any Medicare provider nationwide. Plans C, D, F, G, M, and N also include foreign travel emergency coverage (80% of costs after a $250 deductible, up to $50,000 lifetime maximum).
The Future of Medigap: What to Expect
Plan F Phase-Out Impact
Since the Medicare Access and CHIP Reauthorization Act (MACRA) of 2015, Plans C and F (which cover the Part B deductible) are no longer available to new Medicare beneficiaries as of January 1, 2020. This has made Plan G the most popular choice for new enrollees.
Potential Future Changes
Several proposals have been discussed regarding Medigap's future:
- Limiting first-dollar coverage to encourage more cost-conscious healthcare decisions
- Standardizing pricing methods across states
- Introducing new standardized plans
- Changes to enrollment rules and protections
While no immediate changes are expected, it's important to stay informed through official sources like Medicare.gov and CMS.gov.
Getting Help with Medigap Decisions
State Health Insurance Assistance Program (SHIP)
Every state has a SHIP that provides no-cost, unbiased Medicare counseling, including Medigap guidance. Find your local SHIP at shiphelp.org or call 1-800-MEDICARE (1-800-633-4227).
Medicare.gov Resources
- Find Medigap Policies - Compare policies in your area
- Medicare Publications - Download the official Medigap guide
- Talk to Someone - Connect with Medicare representatives
Working with Licensed Medicare Advisors
Licensed, independent Medicare advisors can help you:
- Understand Medigap plan differences
- Compare premiums from multiple carriers
- Calculate total costs for different scenarios
- Determine optimal enrollment timing
- Complete applications and enrollment
- Provide ongoing support
Our family-run Medicare advisory service specializes in Medigap coverage and has helped thousands of beneficiaries throughout Alabama, Georgia, Florida, Tennessee, and beyond.
Conclusion: Making an Informed Medigap Decision
Medicare Supplement insurance provides comprehensive coverage that fills the gaps in Original Medicare, offering predictable costs, nationwide provider access, and peace of mind. While Medigap premiums are higher than many Medicare Advantage plans, the trade-off is excellent coverage with minimal out-of-pocket costs for Medicare-covered services.
Key takeaways for Medigap shoppers:
- Enroll during your Medigap Open Enrollment Period to avoid medical underwriting
- Compare multiple carriers since coverage is standardized but prices vary
- Consider Plan G for comprehensive coverage or Plan N for lower premiums
- Factor in long-term costs, not just initial premiums
- Understand that Medigap works anywhere in the U.S.
- Remember to add a Part D plan for prescription drug coverage
- Review your coverage annually to ensure it still meets your needs
For personalized guidance on Medicare Supplement insurance and help choosing the right plan, schedule a Medicare review with our licensed advisors. We provide lifetime service and support for all your Medicare needs.
Additional Resources
- Medicare.gov - Official Medicare website
- CMS.gov - Centers for Medicare & Medicaid Services
- SHIP - No-cost Medicare counseling
- Medicare Supplement Plan G: Complete Guide
- Medicare Supplement Plan N: Complete Guide
- Medicare Supplement Plan F: Complete Guide
- Medigap vs Medicare Advantage Comparison
- Medicare Enrollment Calculator
