Medicare · Cornerstone
Supplemental Medicare insurance: how Medigap fills the gaps
Last reviewed July 30, 20268 min readBy the Goodsurance editorial team Reviewed by the Goodsurance editorial team
Original Medicare pays most of your covered medical bills, but it stops short of the whole tab. After you meet the Part B deductible, which is $283 in 2026, Medicare pays 80% of the approved amount and you pay the remaining 20%. That 20% has no annual cap. A single expensive year of treatment could mean thousands of dollars in coinsurance with nothing to stop the meter. Medigap steps into that space.
1What supplemental Medicare insurance actually covers
The hospital side has its own exposure. In 2026, the Part A inpatient deductible is $1,736 per benefit period, not per year, so two separate hospitalizations in the same calendar year can each trigger it. Once you pass day 60 of a stay, coinsurance kicks in at $434 per day for days 61 to 90, and $868 per day for the 60 lifetime reserve days you can draw on after that. Skilled nursing facility care adds $217 per day for days 21 to 100. These are the numbers a supplement policy is built to absorb.
Medigap policies are standardized by federal rule and sold under letter names (Plan A, G, N, and others). Every insurer selling a given letter must offer the same core benefits for that letter, so a Plan G from one company covers the same things as a Plan G from another. What differs is price and service, not the benefit list. There is also a high-deductible version of some plans; in 2026, the CMS-set high-deductible amount for Plans G, F, and J is $2,950, meaning you pay costs up to that figure before the policy begins paying.
In short: Medigap absorbs the deductibles and the uncapped coinsurance that Original Medicare leaves to you.
2Medigap versus Medicare Advantage
These two are often confused, and choosing between them shapes how the rest of your coverage works. Medigap supplements Original Medicare: you keep Part A and Part B, and the policy pays alongside them. Medicare Advantage (Part C) replaces the way you receive Original Medicare by bundling it into a private plan, usually with a network and often with extra benefits built in.
You cannot hold both at the same time. If you enroll in a Medicare Advantage plan, a Medigap policy cannot pay your share of costs, so the two are mutually exclusive by design. The trade-off comes down to structure. Medigap tends to offer broad provider access and predictable cost-sharing, with a monthly premium on top of your Part B premium. Medicare Advantage often carries a low or $0 plan premium but uses networks, referrals, and prior authorization, and it caps your annual spending through a maximum out-of-pocket limit (MOOP) rather than by paying down each bill.
That MOOP is worth understanding if you are weighing the alternatives. In 2026, the federal in-network MOOP cap for Medicare Advantage is $9,250, and plans may set lower limits. According to KFF, the 2026 enrollment-weighted average in-network MOOP is $5,421. Original Medicare, by contrast, has no such cap on its own, which is precisely the gap Medigap is meant to close.
In short: Medigap pays alongside Original Medicare; Medicare Advantage replaces how you get it, and you cannot use both together.
3When to enroll: the window that matters most
Timing is the single most consequential decision in supplemental Medicare insurance, because your health can affect both whether you get a policy and what you pay. The one guaranteed-issue Medigap window is six months long, and it starts the month you are both 65 and enrolled in Part B. During this Medigap open enrollment period, insurers must sell you any policy they offer at the best available rate regardless of your health history. They cannot turn you down or charge you more for pre-existing conditions.
Miss that window and the rules change. Outside of it, in most states an insurer can use medical underwriting: reviewing your health, and potentially declining you or raising your premium. That is why the six-month period carries so much weight. It is not a deadline for enrollment in the abstract; it is the moment your bargaining position is strongest.
This window is separate from your Initial Enrollment Period (IEP) for Medicare itself. The IEP is seven months: the three months before your birthday month, your birthday month, and the three months after. Enrolling in Part B during your IEP is what sets your Medigap clock in motion, so the two fit together but serve different purposes.
In short: your strongest and only guaranteed Medigap window is the six months beginning when you are 65 and on Part B.
4What happens if you apply later
Life does not always cooperate with a six-month window, and it is fair to ask what changes afterward. Once your guaranteed-issue period closes, most states let insurers underwrite applications, so approval and pricing depend on your health. Some people apply years later without trouble; others find their options narrowed. There is no penalty for a late Medigap application the way there is for late Part B or Part D, but the loss of guaranteed issue is the real cost.
A handful of states offer broader access, and the protections differ in kind rather than forming a single flat list. New York and Connecticut require year-round guaranteed issue. Washington lets enrollees switch from one plan to a comparable one. A group of birthday-rule states, including California and Oregon, gives an annual window tied to your birthday during which you can change policies, with widely varying rules; New Mexico's version takes effect in January 2027. Because these categories work so differently, the rules where you live matter more than any general summary.
If your later options feel limited, that is a good moment to talk through the full picture rather than guess. To find out more about coverage, please contact us to discuss plan options.
In short: after your open enrollment window closes, most states allow underwriting, though a few offer year-round or annual access.
5What Medigap does not cover
A supplement policy is focused, and knowing its edges prevents surprises. Medigap does not include prescription drug coverage. For that you add a standalone Part D plan, and it pays to do so on time: going 63 or more days without creditable drug coverage after your Initial Enrollment Period triggers the Part D late-enrollment penalty, which adds 1% of the national base beneficiary premium for each full month you went without, permanently.
Part D itself has improved considerably. In 2026, out-of-pocket spending on covered Part D drugs is capped at $2,100 for the year; once you hit that ceiling, covered drugs cost $0 for the rest of the year. No Part D plan may set a deductible above $615 in 2026, and many set a lower amount or none at all.
Medigap also does not pay for routine dental, vision, hearing aids, or long-term custodial care. It will not cover the 20% coinsurance on services Medicare itself does not approve. One useful detail on hearing: since January 2023, Medicare beneficiaries may see an audiologist for certain non-acute hearing assessments without a physician order, once every 12 months, though this applies to the diagnostic visit only and never to hearing aids.
In short: Medigap fills Medicare cost gaps but excludes drugs, dental, vision, hearing aids, and custodial care.
6Cost factors and the role of income
Medigap premiums vary by the plan letter you choose, your age, where you live, and how the insurer prices its policies, so no single figure applies to everyone. A more comprehensive letter costs more per month but leaves less for you to pay at the point of care; a leaner letter or a high-deductible version lowers the premium and shifts more risk back to you.
Separate from your Medigap premium, you still pay your Part B premium. In 2026, the standard Part B premium is $202.90 per month. Higher-income beneficiaries pay more through an income-related monthly adjustment amount (IRMAA). In 2026, IRMAA begins above $109,000 in modified adjusted gross income for a single filer and $218,000 for a married couple filing jointly. Above those lines, you pay progressively more through income-based tiers, plus a parallel surcharge on Part D. IRMAA uses a two-year lookback, so 2026 premiums are based on your 2024 income, and it works as a cliff: one dollar over a threshold moves you into the full next tier.
If a life-changing event such as retirement or the death of a spouse has lowered your income, you can ask the Social Security Administration to use more recent figures by filing form SSA-44. You can also request reconsideration of an IRMAA determination within 60 days of receiving the notice.
In short: Medigap pricing depends on plan and location, and your separate Part B premium may rise with income through IRMAA.
7How to choose with confidence
The most reliable approach is to sort your priorities before comparing letters. Decide how much predictability you want at the point of care versus how much monthly premium you are willing to carry. Consider how often you travel or see specialists, since Medigap's broad provider access is one of its defining features. Confirm that you have a Part D plan lined up, because Medigap will not cover drugs. And weigh your timing honestly against that six-month guaranteed-issue window, which is where your leverage is greatest.
Because plan pricing and availability are specific to your situation and your zip code, comparisons only become useful once they are grounded in your actual options. Speak with a licensed insurance agent about your plan options. There is no cost to you.
In short: rank predictability, access, and timing first, then compare standardized letters against your own needs.
Common questions about Medicare
Quick answers to common questions
Tap any question to expand. Each question links to a fuller standalone answer.
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.
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 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 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 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 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 hearing aids?
No, not under Original Medicare.
In 2026, Original Medicare (Parts A and B) does not pay for hearing aids or the exams to fit them. Part B does cover diagnostic hearing and balance exams when your doctor orders them to help diagnose or treat a medical condition, and for those you pay 20% after the $283 deductible. Many Medicare Advantage plans, however, include a hearing benefit that helps pay for routine hearing exams and hearing aids, often through a specific network or allowance. If hearing coverage matters to you, it is worth comparing Advantage plans or a standalone hearing plan.
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 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.
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.
Can I see out-of-network doctors on a Medicare Advantage PPO?
Yes.
A Medicare Advantage PPO (Preferred Provider Organization plan, where your Medicare benefits come through a private plan) lets you see doctors and hospitals outside the plan's network, but you usually pay more for out-of-network care than for in-network care. Staying in network keeps your costs lower, while going out of network is allowed and can be worth it if you want a specific provider. This flexibility is a key difference from a Medicare Advantage HMO (Health Maintenance Organization plan), which generally only covers in-network care except in emergencies. With a PPO, you also typically do not need a referral to see a specialist. Keep in mind the provider must accept the plan and Medicare. Emergency and urgent care are covered regardless of network on both plan types. The trade-off with a PPO is more freedom in exchange for generally higher costs than an HMO.
References
- Get started with MedicareOfficial overview of Original Medicare, enrollment periods, Medigap open enrollment, and Part D rules.
- 2026 Medicare Parts A & B premiums and deductiblesCMS fact sheet with the 2026 Part B premium, deductibles, hospital coinsurance, and IRMAA thresholds.
- 2026 Medigap high-deductible options for Plans F, J, and GCMS document setting the 2026 high-deductible amount for standardized Medigap plans.
- Medicare Advantage in 2026KFF analysis of Medicare Advantage premiums, out-of-pocket limits, and prior authorization for comparison with Medigap.
- Part D drug coverage costsMedicare.gov detail on Part D deductibles, the annual out-of-pocket cap, and the late-enrollment penalty.