What Original Medicare doesn’t cover — the gaps Medigap fills
Original Medicare (Parts A and B) covers hospital stays, outpatient visits, lab work, durable medical equipment, and most medically necessary services. What it does not do is cover everything. When you use healthcare, you are responsible for:
- Part A hospital deductible: $1,736 per benefit period in 2026. This is not an annual deductible — it resets with each new benefit period. Two hospitalizations separated by 60 or more days each trigger the full $1,736.
- Part B annual deductible: $283 in 2026. After you meet this, Part B pays 80% of approved outpatient costs.
- Part B coinsurance — the uncapped 20%: You owe 20% of the Medicare-approved amount for doctor visits, outpatient procedures, durable medical equipment, and most other Part B services. There is no annual cap on this 20% under Original Medicare alone. A year of chemotherapy or cardiac rehabilitation can generate tens of thousands of dollars in coinsurance exposure.
- Skilled nursing facility coinsurance: After 20 days of a Medicare-covered SNF stay, daily coinsurance applies for days 21 through 100. See the CMS 2026 Medicare fact sheet for the current daily amount.
- Part B excess charges: Physicians who do not accept Medicare assignment can charge up to 15% above the Medicare-approved rate — you pay the difference.
Medigap policies are sold by private insurers to cover some or all of these costs. The trade-off: a monthly Medigap premium on top of your Part B premium ($185.00/month in 2026).
How Medigap is standardized
Under federal law, Medigap policies sold in most states must follow standardized benefit designs set by the Medicare Supplement Insurance Minimum Standards Model Act. Every insurer selling Plan G must offer the same core benefits as every other insurer selling Plan G. You shop on price and service quality — not on coverage differences between insurers for the same plan letter.
Medicare.gov maintains the official comparison chart showing exactly what each plan letter covers.
Note: Massachusetts, Minnesota, and Wisconsin have their own Medigap standardization systems that differ from the federal letter system.
The 10 standardized plan letters
Ten Medigap plan types are currently sold to new Medicare enrollees. Plans C and F are closed to anyone who became eligible for Medicare after January 1, 2020, per the Medicare Access and CHIP Reauthorization Act (MACRA). People enrolled in those plans before that date keep their coverage.
| Plan | Part A deductible | Part B coinsurance (20%) | Part B deductible | Skilled nursing coinsurance | Part B excess charges | Foreign travel (80%) |
|---|---|---|---|---|---|---|
| A | No | Yes | No | No | No | No |
| B | Yes | Yes | No | No | No | No |
| C * | Yes | Yes | Yes | Yes | No | Yes |
| D | Yes | Yes | No | Yes | No | Yes |
| F * | Yes | Yes | Yes | Yes | Yes | Yes |
| G | Yes | Yes | No | Yes | Yes | Yes |
| K | 50% | 50% | No | 50% | No | No |
| L | 75% | 75% | No | 75% | No | No |
| M | 50% | Yes | No | Yes | No | Yes |
| N | Yes | Yes (with copays) | No | Yes | No | Yes |
*Plans C and F closed to new Medicare enrollees since January 1, 2020.
Plans K and L have annual out-of-pocket maximums — see Medicare.gov for current limits.
Plan G vs. Plan N — the 2026 decision
Plan G and Plan N account for the majority of new Medigap enrollments. Both cover the Part A deductible, most Part B coinsurance, skilled nursing facility coinsurance, and foreign travel emergencies. The differences matter:
Plan G
- Covers 100% of Part B coinsurance after you pay the $283 Part B annual deductible
- Covers Part B excess charges (doctors not accepting Medicare assignment)
- After meeting the $283 deductible: $0 additional out-of-pocket for covered Part B services
Plan N
- Pays Part B coinsurance but requires up to $20 copay per office visit and up to $50 per ER visit (waived if you are admitted as an inpatient)
- Does not cover Part B excess charges — you owe the full excess if a physician charges above the Medicare-approved rate
- Monthly premium is typically $20–$80 lower than Plan G, depending on insurer and location
When Plan N makes sense: If Plan N’s annual premium savings exceed your expected copays plus any excess charge exposure, Plan N can be the better value. For people with infrequent doctor visits who primarily see physicians that accept Medicare assignment, Plan N’s lower monthly premium can result in lower total annual cost.
When Plan G makes sense: If you see specialists frequently, manage a chronic condition with regular outpatient treatment, or prefer a predictable $0 after-deductible cost structure, Plan G eliminates more financial uncertainty.
To check whether your doctors accept Medicare assignment — which matters if you’re considering Plan N — use the Medicare Provider Directory at medicare.gov/care-compare.
The Medigap Open Enrollment Period
Your Medigap Open Enrollment Period (OEP) is six months long. It starts the month you are:
- Age 65 or older, AND
- Enrolled in Medicare Part B
During the OEP, insurers are federally required to offer you any Medigap plan they sell at the standard premium, regardless of your health history. They cannot deny your application or charge more based on pre-existing conditions.
This window does not repeat. Missing the OEP has lasting consequences: in most states, insurers can apply medical underwriting after the OEP, potentially denying coverage or charging substantially higher premiums.
State exceptions: Connecticut, Maine, Massachusetts, and New York maintain year-round guaranteed issue requirements. Check your state insurance department to confirm your state’s rules before your OEP closes.
Guaranteed Issue rights outside the OEP: Federal law also grants guaranteed issue rights in specific situations — losing employer coverage, your Medicare Advantage plan leaving your service area, moving, or your plan going bankrupt. These rights are narrow, time-limited, and not a substitute for buying during the OEP.
How Medigap premiums are priced
Private insurers use one of three rating methods to set Medigap premiums:
- Community-rated: Everyone in the plan pays the same monthly premium regardless of age. Premiums can still increase over time due to medical inflation, but age alone does not increase your rate.
- Issue-age-rated: Premium is based on your age when you first purchase the policy. A 65-year-old pays less than a 72-year-old, and your premium does not increase simply because you get older.
- Attained-age-rated: Premium is based on your current age and increases automatically as you age. Initially lower, but costs typically rise significantly over time.
When comparing Medigap quotes, ask each insurer which rating method applies. An attained-age policy with a lower premium at 65 may cost substantially more by age 80 than a community-rated or issue-age policy with a higher initial premium.
What Medigap does not cover
Medigap supplements Original Medicare — it does not replace it or expand its scope. Medigap policies do not include:
- Prescription drugs — you need a standalone Medicare Part D plan for drug coverage
- Dental, vision, and hearing — not in Original Medicare or Medigap; requires separate private coverage
- Long-term custodial care — Medicare covers only short-term skilled nursing after a qualifying hospital stay; for ongoing custodial care, see long-term care insurance
- Private-duty nursing (with limited exceptions)
- Costs within Medicare Advantage — Medigap is incompatible with Medicare Advantage; it only works with Original Medicare
For the full picture of Medicare — enrollment windows, penalties, and Part D — see the Medicare enrollment guide.
This content is educational and does not constitute insurance or financial planning advice. Medicare supplement plan benefits, premiums, and eligibility rules vary by insurer and state. All Medicare cost-sharing amounts shown are for 2026 and change annually. Visit Medicare.gov or call 1-800-MEDICARE for plan-specific information and licensed agent referrals.