Medicare · Cornerstone
Medicare supplement plans: what they cover, how they work, and when to enroll
Last reviewed September 4, 20269 min readBy the Goodsurance editorial team Reviewed by the Goodsurance editorial team
Understanding Medigap starts with knowing what Original Medicare does not pay. In 2026, the annual Part B deductible is $283. After you meet it, Medicare pays 80% of the approved amount for covered outpatient services, and you pay 20%, according to CMS. That 20% carries no annual ceiling, which means heavy outpatient use can produce large, open-ended totals.
1What Original Medicare leaves unpaid
Hospital costs work differently. Part A charges a deductible of $1,736 per benefit period in 2026, not per calendar year. A benefit period begins the day you are admitted to a hospital or skilled nursing facility (SNF) and ends only when you have been out of an inpatient facility for 60 consecutive days. A second hospitalization after that gap opens a new benefit period and a new $1,736 deductible. Extended stays carry additional coinsurance: days 61 to 90 of a benefit period cost $434 per day in 2026. If a stay stretches beyond 90 days, you may draw on 60 lifetime reserve days at $868 per day in 2026. Once those days are exhausted, Medicare pays nothing.
SNF care has its own tier of cost-sharing. Days 1 to 20 are fully covered after a qualifying 3-day inpatient hospital admission, but days 21 to 100 cost $217 per day in 2026. After day 100, you bear the full daily cost.
Medigap plans pay some or all of these gaps, depending on the plan letter you select.
In short: The Part B coinsurance has no annual cap, and the Part A deductible can recur each benefit period; Medigap is designed to absorb those costs.
Part A hospital costs: what you owe at each stage
A benefit period resets after 60 consecutive days outside any inpatient facility. A second hospitalization after that gap starts a new benefit period and a new deductible.
2How the lettered plans work
Federal law standardizes Medigap benefits. Every carrier that sells a plan labeled "Plan G" must cover exactly the same set of benefits; the plan letter defines what is covered, and price is what varies between insurers. CMS has defined ten standardized plan letters: A, B, C, D, F, G, K, L, M, and N.
One important restriction applies to Plans C and F. Both plans covered the annual Part B deductible, but a 2015 federal law barred new sales of those plans to people who became eligible for Medicare on or after January 1, 2020. If you became eligible before that date, you may still be able to purchase C or F if a carrier in your area offers them. For everyone newly eligible on or after January 1, 2020, the practical field is the remaining letters, of which G and N are the most widely available and commonly purchased.
Plans K and L use partial coverage of some cost-sharing, up to annual out-of-pocket limits, which keeps their premiums lower. Plans A, B, D, and M exist in the market but are less commonly sold. Not every carrier offers every plan letter in every state, and availability varies by county.
In short: All insurers selling the same plan letter must cover identical benefits; once you choose your letter, compare premiums across carriers rather than reading plan brochures.
3The guaranteed-issue window you cannot afford to miss
The most important Medigap enrollment opportunity is the 6-month open enrollment period. It begins the month you are both 65 years old and enrolled in Part B, and it lasts exactly 6 months. During this window, any carrier selling Medigap in your state must sell you any plan it offers at standard rates, regardless of your health history. Denial, higher premiums based on health conditions, and waiting periods for pre-existing conditions are all prohibited.
After the window closes, insurers in most states can apply medical underwriting. They may refuse to sell you a plan, charge a higher premium, or exclude certain conditions from coverage. If you have developed health problems since turning 65, buying Medigap outside of open enrollment can be difficult or expensive in states without additional protections.
Federal law also creates a narrow set of guaranteed-issue rights outside of open enrollment. These apply when specific circumstances change: losing employer-sponsored coverage, your Medigap insurer leaving the market, or disenrolling from a Medicare Advantage (Part C, the private-plan alternative to Original Medicare) plan that is exiting your area. These rights cover specific plan letters, carry strict deadlines, and do not provide blanket access to every plan option.
One common and costly mistake is waiting until a health problem emerges before buying Medigap. In most states, that timing means facing underwriting. The time to act is before or during your 6-month open enrollment window, when your access is unconditional.
In short: Your one guaranteed-issue chance to buy any Medigap plan at standard rates is the 6-month window starting with Part B enrollment at 65; plan around this date.
Your 6-month open enrollment period is the one time any carrier must sell you any Medigap plan at standard rates, no matter your health history. After it closes, insurers in most states can check your health, charge higher premiums, or deny your application.
4Plan G, Plan N, and the high-deductible option
These three plan letters dominate new enrollment for people who became eligible for Medicare after 2019. The table below shows how their coverage structures compare.
| Coverage feature | Plan G | Plan N | High-deductible Plan G |
|---|---|---|---|
| Part A inpatient deductible | Covered | Covered | Covered after $2,950 deductible |
| Part A coinsurance and hospital costs | Covered | Covered | Covered after $2,950 deductible |
| Part B coinsurance | Covered | Covered, with copays up to $20 (office visit) or up to $50 (ER without admission) | Covered after $2,950 deductible |
| Part B excess charges | Covered | Not covered | Covered after $2,950 deductible |
| SNF coinsurance, days 21 to 100 | Covered | Covered | Covered after $2,950 deductible |
| Foreign travel emergency | Covered | Covered | Covered after $2,950 deductible |
| Part B annual deductible | Not covered | Not covered | Not covered |
| 2026 plan deductible | None | None | $2,950 |
Plan G is the most comprehensive option. After you pay the $283 annual Part B deductible in 2026, Plan G covers essentially all remaining Medicare-approved cost-sharing. That includes Part B excess charges: non-participating providers may charge up to 15% above the Medicare-approved amount, and Plan G absorbs that charge. Premiums vary by carrier, rating method, location, and age at enrollment.
Plan N trades coverage of Part B excess charges for a lower monthly premium. Per the federally standardized Plan N design, you pay a copay of up to $20 for some office visits and up to $50 for emergency room visits that do not result in an inpatient admission. In states that prohibit excess charges outright, the practical gap between G and N narrows considerably.
High-deductible Plan G requires you to pay all Medicare-covered costs up to $2,950 in 2026, per CMS, before Plan G's coverage begins. Once you meet that threshold, coverage is identical to standard Plan G. The monthly premium is substantially lower, which suits people in good health who are comfortable covering costs up to the $2,950 threshold in exchange for a lower recurring premium.
None of these three plans cover prescription drugs. Part D (prescription drug coverage) is a separate Medicare program requiring its own enrollment.
To find out more about premiums and plan availability where you live, please contact us to discuss plan options.
In short: Plan G offers the most complete cost-sharing coverage; Plan N lowers the premium with small copays and no excess-charge protection; high-deductible Plan G lowers the premium further in exchange for a $2,950 annual threshold.
- Covers Part B coinsurance in full after the annual deductible
- Covers Part B excess charges from non-participating providers
- No plan-level deductible
- Higher monthly premium than Plan N or high-deductible Plan G
- Lower monthly premium than Plan G
- Small copays for some office visits and ER visits without admission
- Does not cover Part B excess charges
- Lowest monthly premium of the three
- You pay all Medicare costs up to $2,950 before coverage begins
- Full Plan G coverage once the annual threshold is met
5What Medigap does not cover
Even the broadest Medigap plan letters have defined limits. No standardized Medigap plan covers the following:
Prescription drugs. Part D is a separate Medicare program. Medigap plans issued since 2006 cannot include outpatient drug coverage. To cover your prescriptions, you must enroll in a standalone Part D plan or a Medicare Advantage plan that includes drug coverage.
Routine dental, vision, and hearing. Original Medicare covers these only in limited clinical circumstances, such as a dental procedure required before certain cardiac surgeries. Medigap follows the same boundary. Routine dental care, eyeglasses, hearing aids, and hearing exams require either a separate supplemental dental or vision policy, or a Medicare Advantage plan that includes those benefits. If your plan covers hearing aids or dental implants, check your Medicare Advantage plan for your specific coverage.
Long-term care. Medicare and Medigap do not cover custodial care, which is assistance with daily living activities in a nursing home or at home. Long-term care insurance is an entirely different product category.
Most care outside the United States. Plans C, D, F, G, M, and N include a foreign travel emergency benefit that pays 80% of covered emergency costs after a per-trip deductible, up to a lifetime maximum. Plans A, B, K, and L do not include this feature. The benefit applies to genuine medical emergencies abroad, not routine or ongoing treatment.
In short: Medigap pays Medicare's cost-sharing gaps but does not replace Part D drug coverage, routine dental, vision, hearing, or long-term care.
What Medigap covers and what it does not
Covers
- Part A hospital cost-sharing, including the inpatient deductible and daily coinsurance
- Part B outpatient coinsurance (the uncapped 20% Medicare leaves open)
- Skilled nursing facility coinsurance for days 21 to 100
- Foreign travel emergencies (most plan letters)
Does not cover
- Prescription drug coverage (requires a separate Part D plan)
- Routine dental, vision, and hearing care
- Long-term care and custodial assistance
- Most medical care outside the United States
Plans C, D, F, G, M, and N include a foreign travel emergency benefit. Plans A, B, K, and L do not.
6How Medigap premiums are priced
Three rating methods determine how insurers set and adjust Medigap premiums, and the method has a significant effect on your long-term cost.
Issue-age rated. The premium is based on your age when you first purchase the plan. It does not increase simply because you grow older. General market-wide adjustments and inflation can still push rates up, but your cost is anchored to your entry age rather than to a running age clock.
Attained-age rated. The premium rises as you get older. These plans often carry lower premiums at 65 but can become significantly more expensive in your 70s and 80s. Over a long retirement, total lifetime spending may exceed what an issue-age plan would have cost.
Community rated. Everyone in the same geographic area pays the same premium regardless of age. Younger enrollees may pay more at entry compared with an attained-age plan, but the rate does not increase with age.
Beyond the rating method, premiums vary by state, county, tobacco use status, and the specific carrier. Because the benefits for a given plan letter are federally defined and identical across insurers, comparing premiums directly across carriers is the most efficient way to find value. Carriers adjust rates periodically, so a competitively priced plan at enrollment may not remain so in later years. Reviewing your premium against the current market every few years is a reasonable habit.
Some carriers offer household discounts when two people in the same household both purchase Medigap coverage. Availability and discount amounts vary by carrier and state.
In short: The rating method determines how your premium grows over time; attained-age plans start lower but often cost more in your 70s and 80s than issue-age or community-rated alternatives.
- Premium is set at your age when you first buy
- Does not rise just because you get older
- May cost more at age 65 than an attained-age plan
- Often the lowest premium at age 65
- Premium rises each year as you age
- Can cost significantly more in your 70s and 80s
- Same premium for all ages in your area
- Does not increase as you get older
- May be higher than attained-age plans at age 65
7Accessing Medigap after the guaranteed-issue window
Missing the open enrollment window does not permanently close the door, but it does change the landscape. In most states, insurers can medically underwrite your application, which may result in a higher premium, a coverage exclusion, or a denial depending on your health history.
Several states have enacted consumer protections that expand access beyond the federal rules. These protections fall into recognizable categories rather than a single national standard:
Year-round guaranteed issue. A small number of states, including New York and Connecticut, require carriers to sell Medigap to any Medicare beneficiary at any time, at standard rates, regardless of health history.
Birthday-rule protections. About 16 states have enacted birthday-rule laws that allow beneficiaries to switch to a Medigap plan of equal or lesser benefits during a short window around their birthday each year, without medical underwriting. California and Oregon are among the states with this protection. New Mexico's birthday-rule law takes effect January 2027. The window length, eligible plan letters, and procedural requirements vary significantly from state to state.
Plan-to-plan switching. Washington state allows policyholders to switch from one Medigap plan to another at any time, subject to the same insurer, without underwriting.
Outside of these state-specific frameworks, the main path to Medigap after the federal open enrollment window is either a federal guaranteed-issue right tied to a qualifying event or full medical underwriting. If underwriting is required, the outcome depends on your health history and the individual carrier's guidelines.
To find out more about your specific options in your state, please contact us to discuss plan options.
In short: State-level birthday-rule laws and year-round guaranteed-issue states expand access for some beneficiaries, but medical underwriting applies in most states after the federal 6-month window.
Common questions about Medicare
Quick answers to common questions
Tap any question to expand. Each question links to a fuller standalone answer.
Does Medicare pay for hearing aids
Original Medicare does not cover hearing aids or fittings.
Some Medicare Advantage plans may include a hearing benefit, but what they cover varies by plan.
Does Medicare cover ambulance services?
Yes, in limited situations.
Medicare Part B covers emergency ambulance transportation when traveling any other way could endanger your health, taking you to the nearest appropriate hospital or facility. You pay 20% of the Medicare-approved amount after the $283 Part B deductible in 2026. Air ambulance is covered only when ground transport cannot reach you or would take too long. Non-emergency ambulance trips, for example to dialysis, are covered only when a doctor provides a written order stating they are medically necessary. Medicare does not cover ambulance rides taken purely for convenience.
Does Medicare cover skilled nursing facility care?
Yes, on a short-term basis.
Medicare Part A covers skilled nursing facility (SNF) care after a qualifying inpatient hospital stay of at least 3 days, when you need daily skilled care like nursing or therapy. In 2026 you pay $0 for days 1 through 20 of each benefit period, $217 per day for days 21 through 100, and all costs after day 100. Coverage is for skilled care while you recover, not for long-term or custodial care (help with daily activities like bathing or dressing), which Medicare does not cover. Long-term nursing home care is generally paid through Medicaid or private funds.
Does Medicare cover physical therapy?
Yes.
Medicare Part B covers outpatient physical therapy that is medically necessary to treat your condition. You pay 20% of the Medicare-approved amount after the yearly Part B deductible ($283 in 2026). There is no longer a hard dollar cap on therapy, but once your physical and speech therapy together pass $2,480 in 2026, your therapist must add a note (called a KX modifier) confirming you still need care. Claims above $3,000 may be reviewed for medical necessity. Part A covers physical therapy you receive as a hospital inpatient or in a skilled nursing facility. A doctor or therapist must set up and regularly review your plan of care.
Does Medicare cover mental health services?
Yes.
Medicare covers mental health care across its parts in 2026. Part B covers outpatient services like therapy, counseling, and visits with psychiatrists, psychologists, and clinical social workers, and since 2024 it also covers marriage and family therapists and mental health counselors. You pay 20% of the Medicare-approved amount after the $283 deductible, and one depression screening each year is free. Part A covers inpatient mental health care, with a lifetime limit of 190 days in a freestanding psychiatric hospital. Part D covers most mental health medications. Many of these services are also available by telehealth, and Medicare Advantage plans cover at least the same benefits.
Does Medicare cover chiropractic care?
Partly.
Medicare Part B covers one specific chiropractic service: manual manipulation of the spine to correct a subluxation (when one or more bones of the spine are out of position) that a doctor confirms is medically necessary. You pay 20% of the Medicare-approved amount after the $283 Part B deductible in 2026. Medicare does not cover other services a chiropractor might offer, such as X-rays, massage therapy, acupuncture, or routine wellness visits, so you would pay the full cost for those. Some Medicare Advantage plans include extra chiropractic or wellness benefits beyond this.
Does Medicare cover home health care?
Yes, when you qualify.
Medicare Parts A and B cover home health care if a doctor certifies that you are homebound (leaving home takes a major effort) and need part-time skilled care, such as skilled nursing, physical therapy, occupational therapy, or speech therapy. A Medicare-certified home health agency must provide the care under a plan your doctor reviews. You pay $0 for covered home health visits in 2026, and 20% for any durable medical equipment. Medicare does not cover 24-hour home care, meal delivery, or homemaker services like cleaning when that is the only care you need.
Does Medicare cover vision care?
Mostly no for routine care.
In 2026, Original Medicare does not cover routine eye exams for glasses or contact lenses, and it does not pay for the glasses or contacts themselves. It does cover some medical eye care: yearly glaucoma screenings for people at high risk, diabetic retinopathy exams, treatment for eye diseases, and cataract surgery (including one pair of standard glasses or contacts afterward). For those covered services you pay 20% after the $283 Part B deductible. Many Medicare Advantage plans add a routine vision benefit covering eye exams and an allowance for glasses.
Does Medicare cover hearing aids?
Original Medicare does not cover hearing aids or the exams used to fit them.
Some Medicare Advantage plans include a hearing benefit, but coverage varies by plan.
Does Medicare cover diabetes supplies and testing?
Yes.
In 2026 Medicare covers most diabetes care across two parts. Part B (outpatient care and equipment) covers blood sugar monitors, test strips, lancets, and continuous glucose monitors (CGMs) as durable medical equipment, plus diabetes screenings and a self-management training program. You pay 20% of the Medicare-approved amount after the $283 Part B deductible. Part D (drug coverage) covers insulin and related supplies like syringes, and in 2026 your insulin is capped at $35 for a month's supply. If you have a Medicare Advantage plan, it covers at least the same diabetes benefits, sometimes with added extras.
Does Medicare cover durable medical equipment?
Yes.
Medicare Part B covers durable medical equipment (DME): reusable medical gear your doctor prescribes for use at home, such as wheelchairs, walkers, hospital beds, oxygen equipment, CPAP machines, and blood sugar monitors. You pay 20% of the Medicare-approved amount after the $283 Part B deductible in 2026, and Medicare pays the other 80%. To be covered, the item must be ordered by a Medicare-enrolled doctor and supplied by a Medicare-enrolled supplier, and some items are rented rather than bought. Equipment meant mainly for use outside the home, or only for comfort or convenience, is not covered.
Which is better, Medigap or Medicare Advantage?
Neither is better for everyone; they suit different needs.
Medigap (also called Medicare Supplement, a private policy that pairs with Original Medicare) lets you see any doctor nationwide who accepts Medicare with no network and very predictable out-of-pocket costs, but you pay a monthly Medigap premium and add a separate Part D drug plan. Medicare Advantage (Part C, your Medicare benefits through a private plan) often has a lower or $0 plan premium, bundles drug coverage and extras like dental and vision, and caps your yearly out-of-pocket costs, but uses provider networks and may require prior approval. People who travel, want maximum doctor freedom, and prefer steady costs often lean Medigap; people who want low premiums, extras, and a network they are comfortable with often lean Medicare Advantage. With both, you still pay the Part B premium ($202.90 per month in 2026). To find out which fits your situation, reach out to a licensed Goodsurance advisor at 1-888-301-8091 (TTY 711), Mon to Fri 8 am to 5 pm PT.
References
- 2026 Medicare Parts B premiums and deductiblesCMS fact sheet with verified 2026 figures for Part A and Part B cost-sharing, including the inpatient deductible, SNF coinsurance, Part B deductible, and lifetime reserve day rates.
- Compare Medigap plan benefitsMedicare.gov side-by-side chart of all standardized Medigap plan letters A through N, including the Plan N copay structure and foreign travel emergency benefit.
- 2026 Medigap high-deductible amounts for Plans F, G, and JCMS document confirming the 2026 high-deductible Medigap threshold of $2,950 for Plans F, G, and J.
- KFF Medicare research and policy analysisKFF Medicare policy hub covering Medigap state-level access rules, birthday-rule laws, and enrollment trends across plan letters.