Medicare Supplement Insurance (also called Medigap) helps pay for costs that Original Medicare doesn't cover—like deductibles, copays, and coinsurance. If you have Original Medicare and want to reduce your out-of-pocket expenses, a Medigap policy can provide valuable financial protection.
This guide explains all 10 standardized Medigap plans (A, B, C, D, F, G, K, L, M, and N) so you can understand your options and make an informed decision.
What Is Medicare Supplement Insurance?
Medigap is private insurance that supplements your Original Medicare (Part A and Part B) coverage. It's designed to fill the "gaps" in Medicare—the costs you'd otherwise pay out of pocket.
What Medigap Covers
- Part A coinsurance and hospital costs (up to 365 additional days after Medicare benefits end)
- Part B coinsurance or copayment (the 20% you normally pay)
- Part A hospice care coinsurance or copayment
- Blood (first 3 pints)
- Part A deductible (depending on plan)
- Part B deductible (Plans C and F only, for those eligible)
- Part B excess charges (depending on plan)
- Skilled nursing facility coinsurance (depending on plan)
- Foreign travel emergency care (depending on plan)
What Medigap Does NOT Cover
- Prescription drugs (you need a separate Part D plan)
- Long-term care
- Vision or dental
- Hearing aids
- Private-duty nursing
Medigap vs Medicare Advantage
You cannot have both a Medigap policy and a Medicare Advantage plan. Medigap works only with Original Medicare. If you have Medicare Advantage, you must leave that plan and return to Original Medicare before enrolling in Medigap.
How Medigap Works with Original Medicare
When you have a Medigap policy, here's how claims work:
- You receive a Medicare-covered service
- Original Medicare pays its share
- Your Medigap policy pays some or all of the remaining costs
For example, if you have a doctor visit that costs $200:
- Medicare Part B pays 80% ($160)
- You would normally owe 20% ($40)
- Your Medigap policy pays that $40 (if your plan covers Part B coinsurance)
This means you have predictable costs and are protected from large, unexpected medical bills.
Standardized Plans Explained
Medigap plans are standardized by the federal government. This means:
- Plan G is Plan G regardless of which insurance company sells it
- The benefits are identical—only the premium varies by company
- You can compare prices knowing you're getting the exact same coverage
There are 10 standardized plans available in most states: A, B, C, D, F, G, K, L, M, and N.
Plans C and F Are Not Available to Everyone
If you became eligible for Medicare on or after January 1, 2020, you cannot buy Plan C or Plan F. These plans cover the Part B deductible, which Congress eliminated for new Medicare beneficiaries.
State Variations
Massachusetts, Minnesota, and Wisconsin have their own standardized Medigap plans that differ from the federal standard. If you live in one of these states, contact your state insurance department for details.
Coverage Comparison Chart
This chart shows what each standardized Medigap plan covers. A checkmark means the plan covers the benefit 100%. Some plans offer partial coverage, noted in the chart.
| Benefit | A | B | C* | D | F* | G | K | L | M | N |
|---|---|---|---|---|---|---|---|---|---|---|
| Part A coinsurance + 365 extra hospital days | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ |
| Part B coinsurance/copay | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | 50% | 75% | ✓ | ** |
| Blood (first 3 pints) | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | 50% | 75% | ✓ | ✓ |
| Part A hospice coinsurance | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | 50% | 75% | ✓ | ✓ |
| Skilled nursing facility coinsurance | ✗ | ✗ | ✓ | ✓ | ✓ | ✓ | 50% | 75% | ✓ | ✓ |
| Part A deductible ($1,632 in 2025) | ✗ | ✓ | ✓ | ✓ | ✓ | ✓ | 50% | 75% | 50% | ✓ |
| Part B deductible ($257 in 2025) | ✗ | ✗ | ✓ | ✗ | ✓ | ✗ | ✗ | ✗ | ✗ | ✗ |
| Part B excess charges | ✗ | ✗ | ✗ | ✗ | ✓ | ✓ | ✗ | ✗ | ✗ | ✗ |
| Foreign travel emergency (80%) | ✗ | ✗ | ✓ | ✓ | ✓ | ✓ | ✗ | ✗ | ✓ | ✓ |
| Out-of-pocket limit | N/A | N/A | N/A | N/A | N/A | N/A | $7,060 | $3,530 | N/A | N/A |
*Plans C and F are only available to those eligible for Medicare before January 1, 2020.
**Plan N pays 100% of Part B coinsurance except for up to $20 copay for office visits and up to $50 copay for ER visits (waived if admitted).
Plan-by-Plan Breakdown
Plan A — Basic Benefits Only
The most basic Medigap plan. Covers the core benefits required by federal law but nothing extra.
- Part A coinsurance and 365 extra hospital days
- Part B coinsurance (20%)
- First 3 pints of blood
- Part A hospice coinsurance
Best for: Those who want minimal coverage at the lowest premium and are comfortable paying deductibles and SNF costs out of pocket.
Plan B — Basic + Part A Deductible
Adds Part A deductible coverage to the basic benefits.
- Everything in Plan A
- Part A deductible ($1,632 in 2025)
Best for: Those who want help with hospital admission costs but don't need comprehensive coverage.
Plan C — Comprehensive (Pre-2020 Eligibility Only)
One of the most complete plans available, covering almost everything including the Part B deductible.
- Everything in Plan A and B
- Skilled nursing facility coinsurance
- Part B deductible
- Foreign travel emergency
Note: Only available if you became eligible for Medicare before January 1, 2020.
Plan D — Like Plan C Without Part B Deductible
Comprehensive coverage similar to Plan C, but you pay the Part B deductible yourself.
- Part A deductible
- Skilled nursing facility coinsurance
- Foreign travel emergency
- Does NOT cover Part B deductible or excess charges
Best for: Those who want comprehensive coverage but don't need Part B deductible coverage (or became eligible for Medicare after 2020).
Plan F — Most Comprehensive (Pre-2020 Eligibility Only)
The most complete Medigap plan available. Covers everything, including Part B excess charges.
- Everything in Plan C
- Part B excess charges (charges above Medicare-approved amounts)
Note: Only available if you became eligible for Medicare before January 1, 2020. Often the most expensive plan.
Plan G Most Popular
Nearly identical to Plan F, but you pay the Part B deductible. This is the most comprehensive plan available to those new to Medicare after 2020.
- Part A deductible and coinsurance
- Part B coinsurance (after you pay the deductible)
- Skilled nursing facility coinsurance
- Part B excess charges
- Foreign travel emergency
- Does NOT cover Part B deductible ($257 in 2025)
Best for: Most people. Comprehensive coverage with lower premiums than Plan F, and you're only responsible for the small Part B deductible.
Plan K — High-Deductible Option with Cost-Sharing
A budget option that covers 50% of most costs until you reach the out-of-pocket limit.
- 50% of most covered benefits
- Out-of-pocket limit: $7,060 (2025)
- 100% coverage after reaching the limit
Best for: Healthy individuals who want lower premiums and can handle higher out-of-pocket costs if needed.
Plan L — Moderate Cost-Sharing Option
Similar to Plan K but with 75% cost-sharing and a lower out-of-pocket limit.
- 75% of most covered benefits
- Out-of-pocket limit: $3,530 (2025)
- 100% coverage after reaching the limit
Best for: Those who want lower premiums than full-coverage plans but less risk than Plan K.
Plan M — Partial Part A Deductible Coverage
Covers only 50% of the Part A deductible but includes other comprehensive benefits.
- 50% of Part A deductible
- Full Part B coinsurance
- Skilled nursing facility coinsurance
- Foreign travel emergency
Best for: Those who want to save on premiums and are comfortable paying half the Part A deductible when hospitalized.
Plan N Popular Choice
Similar to Plan G but with small copays for office and ER visits. Often significantly cheaper than Plan G.
- Part A deductible and coinsurance
- Part B coinsurance with copays (up to $20 for office visits, up to $50 for ER)
- Skilled nursing facility coinsurance
- Foreign travel emergency
- Does NOT cover Part B deductible or excess charges
Best for: Those who want comprehensive coverage at a lower premium and don't mind small copays for doctor visits.
Most Popular Plans
While the "best" plan depends on your individual situation, these are the most commonly chosen options:
Plan G — The New Standard
Plan G has become the most popular Medigap plan, especially since Plan F is no longer available to new Medicare beneficiaries. It offers comprehensive coverage with the only out-of-pocket cost being the annual Part B deductible ($257 in 2025). Most people find the premium savings over Plan F (for those who can get it) more than offset paying this small deductible.
Plan N — Best Value
Plan N is often 15-30% cheaper than Plan G with nearly the same coverage. The trade-off is small copays (up to $20 for office visits, up to $50 for ER visits not resulting in admission) and no coverage for Part B excess charges. For many people, the premium savings make Plan N an excellent value.
Understanding Medigap Costs
How Insurance Companies Price Plans
While benefits are standardized, premiums vary significantly between insurance companies. They use three pricing methods:
- Community-rated (no age rating): Everyone pays the same premium regardless of age. Your premium won't increase just because you get older.
- Issue-age-rated: Premium is based on your age when you buy the policy. It won't increase due to aging (but may increase due to inflation).
- Attained-age-rated: Premium is based on your current age and increases as you get older. Usually starts lowest but becomes most expensive over time.
Long-Term Cost Consideration
Community-rated or issue-age-rated policies often save money in the long run, even if they start with higher premiums. Attained-age-rated policies may seem attractive initially but can become very expensive as you age.
Typical Premium Ranges
Medigap premiums vary by location, age, gender, and insurance company. As a general guide:
- Plan G: $150-$350/month
- Plan N: $100-$250/month
- Plan F: $175-$400/month (if eligible)
- High-deductible plans (K, L): $30-$100/month
Always get quotes from multiple insurance companies—the same Plan G can cost $100+ more per month from one company versus another.
When to Enroll
Your Medigap Open Enrollment Period Is Critical
You have a one-time, 6-month window starting when you're 65+ AND enrolled in Part B. During this period, insurance companies cannot deny you or charge more due to health conditions. After this window closes, you may be denied coverage or charged significantly higher premiums.
Medigap Open Enrollment Period
Your Medigap Open Enrollment Period:
- Begins the first day of the month you're 65 or older AND enrolled in Part B
- Lasts 6 months
- Guarantees you can buy any Medigap policy sold in your state
- Cannot be denied or charged more due to pre-existing conditions
- Only happens once—there's no annual enrollment period for Medigap
Enrolling Outside Your Open Enrollment Period
If you miss your Medigap Open Enrollment Period, insurance companies can:
- Use medical underwriting
- Deny you coverage based on health conditions
- Charge higher premiums based on your health
- Impose waiting periods for pre-existing conditions
Some states have additional protections, and there are limited "guaranteed issue" situations (like leaving a Medicare Advantage plan), but these are exceptions.
How to Choose the Right Plan
Questions to Ask Yourself
- What's your budget? Higher premiums = lower out-of-pocket costs when you need care. Lower premiums = more cost-sharing when you use services.
- How's your health? If you have chronic conditions or anticipate significant medical care, comprehensive plans (G or F if eligible) often make sense.
- Do you travel internationally? Plans C, D, F, G, M, and N include foreign travel emergency coverage.
- How do you feel about copays? Plan N's small copays bother some people but save others significant premium dollars.
- What's your risk tolerance? Plans K and L have lower premiums but more cost-sharing until you hit the out-of-pocket limit.
General Recommendations
- For most people: Plan G offers the best balance of comprehensive coverage and value
- For budget-conscious enrollees: Plan N provides excellent coverage at lower premiums
- For healthy, cost-conscious people: Plan K or L with lower premiums and out-of-pocket limits
- For those eligible for Plan F: Compare Plan F and Plan G premiums—often paying the Part B deductible and choosing Plan G saves money overall
Get Multiple Quotes
Since all Plan G policies (for example) offer identical coverage, the only difference is price and the insurance company's financial stability. Get quotes from at least 3-5 companies and check their AM Best ratings for financial strength.