Can You Have Medicare Without a Supplement Plan? (2026)

Direct Answer: Yes, But There Is No Cap

Yes. Original Medicare, Part A and Part B, works on its own and no federal rule requires you to buy a Medicare Supplement (Medigap) policy. Skip one, and you take on the Part A deductible ($1,736 per benefit period in 2026), the Part B deductible ($283 in 2026), and 20% coinsurance on most Part B services with no yearly out-of-pocket cap. Medicare Advantage, not Medigap, is the main way to cap that exposure.

What Original Medicare Pays on Its Own in 2026

Original Medicare splits into two federal programs: Part A (hospital insurance) and Part B (medical insurance). Part A charges a $1,736 deductible per benefit period in 2026, and if a hospital stay runs past 60 days, coinsurance jumps to $434 a day for days 61 through 90 and $868 a day for lifetime reserve days beyond that. Skilled nursing facility care costs nothing for the first 20 days, then $217 a day for days 21 through 100 in 2026, all federal amounts published by CMS.

Medicare Part B carries a $283 deductible in 2026, and after that you generally pay 20% coinsurance for doctor visits, outpatient care, durable medical equipment, and most other Medicare Part B services, plus the standard $202.90 monthly premium (higher for beneficiaries with income above IRMAA thresholds). Unlike ACA-compliant marketplace plans, which must cover the ten essential health benefits and cap total in-network cost-sharing, Original Medicare Part A and Part B have no built-in annual out-of-pocket maximum. Medicare Part D, by contrast, already has its own $2,100 out-of-pocket cap in 2026, which is why the gap sits specifically in Part A and Part B.

What Medicare Advantage Adds Instead of a Supplement

Medicare Advantage is the most common substitute for a Medigap policy. Every Medicare Advantage plan is legally required to cap in-network out-of-pocket spending on Part A and Part B services at $9,250 in 2026, and the federal combined in-network-plus-out-of-network ceiling is $13,900. Most plans set their limit lower: the 2026 enrollment-weighted average is $5,421 in-network and $9,825 combined, according to KFF. Many Medicare Advantage plans also charge $0 monthly premiums and bundle in dental, vision, and hearing benefits that Original Medicare does not cover.

The tradeoff is network. Medicare Advantage plans are typically HMOs or PPOs with a defined list of doctors and hospitals, prior authorization requirements for many services, and regional coverage areas, while Original Medicare works with any provider nationwide who accepts Medicare. You cannot buy a Medigap policy while enrolled in Medicare Advantage; it is not legal for an insurer to sell you one for that purpose.

Your Cost Exposure Without a Supplement (2026)

Without Medigap or a Medicare Advantage out-of-pocket cap, a single serious hospitalization can run into tens of thousands of dollars. A 10-day hospital stay past day 60 in 2026 adds $4,340 in coinsurance ($434 times 10 days) on top of the $1,736 Part A deductible. A prolonged skilled nursing stay of 40 days beyond the free 20-day window adds $8,680 in coinsurance ($217 times 40 days). Outpatient care and specialist visits add 20% Part B coinsurance with no ceiling. For someone with a chronic condition needing frequent care, annual out-of-pocket costs on Original Medicare alone commonly exceed $5,000 to $10,000, and there is no federal limit stopping that number from climbing higher in a bad year.

Medigap: The Standalone Supplemental Option

Medigap policies are standardized, federally regulated insurance products sold by private companies to work alongside Original Medicare, filling in deductibles, coinsurance, and, for some plans, foreign travel emergency care. Ten standardized plans are sold in most states: A, B, D, G, K, L, M, and N, plus legacy Plans C and F that are closed to anyone who became eligible for Medicare on or after January 1, 2020. Plan G is the most popular choice for new enrollees and typically covers everything except the Part B deductible.

Pricing depends heavily on when you buy. You get a six-month Medigap open enrollment window starting the month you turn 65 and enroll in Part B, during which insurers cannot use medical underwriting or deny you for a preexisting condition. Buy outside that window, or after switching from Medicare Advantage back to Original Medicare, and an insurer can medically underwrite you, charge more, or in some states deny coverage entirely based on your health history.

Who Reasonably Skips a Supplement

Several groups go without Medigap and manage the risk deliberately. People dual-eligible for Medicare and Medicaid typically do not need Medigap because Medicaid covers Original Medicare's cost-sharing. Retirees with employer or union retiree health coverage, or veterans using VA benefits alongside Medicare, often already have a secondary payer that limits their exposure. Healthy retirees on a tight budget sometimes choose a $0-premium Medicare Advantage plan specifically because it has a built-in out-of-pocket cap, even without paying for Medigap. What is riskier is having Original Medicare with zero secondary coverage of any kind, since that combination carries the highest uncapped exposure.

How to Decide: Original Medicare Alone vs Medigap vs Medicare Advantage

Start at Medicare.gov's plan finder to compare Medigap premiums and Medicare Advantage plans available in your ZIP code side by side. If you travel often, see many specialists, or want predictable costs, Medigap plus Part D usually costs more monthly but caps your risk. If you want a lower monthly premium and extra benefits like dental and vision and can accept a network and prior authorization, Medicare Advantage is built to cap your annual exposure without a separate Medigap purchase. Either way, going without any backup to Original Medicare Part A and Part B is the only option with no ceiling on what you could owe in 2026.

Does Original Medicare have an out-of-pocket maximum?

No. Original Medicare Part A and Part B have no built-in annual out-of-pocket maximum in 2026. You pay the Part A deductible ($1,736 per benefit period), the Part B deductible ($283), and 20% coinsurance on most Part B services indefinitely unless you add a Medigap policy or switch to Medicare Advantage, which is required to cap costs.

What happens if I don't buy a Medigap policy?

You remain fully responsible for Original Medicare's deductibles and 20% coinsurance with no annual cap. Most years this may total a few hundred to a few thousand dollars, but a serious hospitalization or extended skilled nursing stay in 2026 can push out-of-pocket costs well past $10,000 since there is no federal ceiling.

Is Medicare Advantage a substitute for a Medicare Supplement?

Functionally, yes, for the out-of-pocket cap. Medicare Advantage plans must cap in-network Part A and Part B costs at $9,250 in 2026 ($13,900 combined), while Medigap has no legal cap requirement of its own but often reduces your cost-sharing to near $0. You cannot have both at once; Medigap only pairs with Original Medicare.

When can I buy a Medigap policy without medical underwriting?

During your six-month Medigap open enrollment period, which starts the month you turn 65 and are enrolled in Part B. Insurers must sell you any Medigap plan they offer at that time regardless of health history. Outside that window, insurers in most states can medically underwrite you or decline coverage.

Can I have Medicare Advantage and Medigap at the same time?

No. Federal rules prohibit insurers from selling a Medigap policy to someone enrolled in a Medicare Advantage plan, since the two products solve the same problem (capping cost-sharing) in different ways. If you want Medigap, you generally need to disenroll from Medicare Advantage and return to Original Medicare first.

What if I have retiree or employer coverage instead of Medigap?

Employer or union retiree health coverage often acts as a secondary payer to Original Medicare, covering some or all of the deductibles and coinsurance Medigap would otherwise cover. Check your plan's summary of benefits, since coverage generosity varies widely by employer and some retiree plans are thinner than a Medigap policy.

Is it risky to go without any supplemental coverage?

Yes, financially. Original Medicare alone leaves you exposed to unlimited 20% coinsurance on Part B services and per-day hospital coinsurance that can run into the thousands during an extended stay. It is legal and some people manage the risk deliberately, but for most beneficiaries either Medigap or Medicare Advantage meaningfully reduces that exposure.

What's the cheapest way to protect against high Medicare costs in 2026?

A $0-premium Medicare Advantage plan is usually the lowest-cost way to get an annual out-of-pocket cap, since it adds no extra monthly premium beyond standard Part B. Medigap costs more monthly ($110 to $480+ depending on the plan letter, state, and age) but reduces cost-sharing further and keeps you on the nationwide Original Medicare network.