Original Medicare does not ordinarily pay every dollar of a Part B service after the annual deductible has been met. Medicare’s 2026 cost guidance says beneficiaries usually pay 20% of the cost for each covered service or item after paying the Part B deductible, as long as the physician or other provider accepts the Medicare-approved amount as full payment. The word “usually” is part of the rule, because coverage and cost sharing can depend on the service and provider arrangement.
The General Rule Starts After the Annual Deductible
The Medicare.gov cost table lists a $283 Part B deductible for 2026. It says that amount is paid once each year before Original Medicare begins to pay. After that threshold, the table lists the general Part B coinsurance as usually 20% of the Medicare-approved cost for covered services and items.
Deductible and coinsurance are sequential, not interchangeable. The deductible is the amount paid first in the year for Part B-covered care. Coinsurance is the continuing percentage share that can apply afterward. A notice that shows both amounts is not necessarily duplicating a charge; it may be reflecting two different steps in the benefit’s cost structure.
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Medicare-Approved Amount Is the Relevant Base
The 20% share is tied to the Medicare-approved amount, not automatically to a provider’s initial list price. Medicare’s wording also assumes the doctor or health care provider accepts assignment, meaning the provider agrees to accept the approved amount as full payment. Provider participation affects how a bill is processed and should be checked before a general 20% rule is treated as a final estimate.
For example, a covered office service can carry a different dollar amount from a covered outpatient procedure even if the percentage rule is the same. The amount changes because the approved amount and any service-specific payment rule change. Twenty percent is therefore a cost-sharing formula, not a universal dollar charge.
Some Part B Services Have Their Own Cost Rules
The same Medicare table lists $0 for covered clinical laboratory services. It also describes separate charges for outpatient hospital care, including a hospital copayment for each service in an outpatient department. Those entries illustrate why the general rule cannot replace a reading of the benefit category.
Preventive services, ambulance transport, durable medical equipment and care delivered in a hospital setting can each involve additional coverage details. A person should not assume a charge is wrong merely because it is not exactly 20%, but should compare the service description, provider setting and Medicare Summary Notice with the applicable coverage language.
That distinction is particularly important when a single episode includes more than one billable component. A professional service, a facility service and durable equipment can be governed by different Medicare entries even when they arise from the same course of care. The general coinsurance percentage remains a useful baseline, but the official service category and setting determine whether a specific bill follows it or a separate rule.
Original Medicare Is Not Every Plan’s Price Schedule
Medicare Advantage plans set plan-specific deductibles, copayments and coinsurance while still covering Medicare services. Those plans also have annual out-of-pocket limits for covered services. A Medigap policy may help with Original Medicare’s coinsurance, depending on its terms. Medicaid or a Medicare Savings Program can also affect Medicare cost responsibility for people who meet the relevant state program rules.
None of those arrangements changes the published Original Medicare baseline. The 20% rule belongs to Original Medicare Part B after the deductible and under the assignment condition. A beneficiary’s final bill may be lower, higher or structured differently because of other coverage, noncovered services or provider billing status.
The Percentage Does Not Mean Every Care Episode Costs the Same
Part B includes a wide range of medical services and items. The percentage can be the same while the dollar exposure varies greatly with the approved amount, number of services and setting. An outpatient department can add a facility copayment, while a physician office service may have only the professional component. The annual deductible affects early-year services differently from later-year services.
For 2026, Medicare’s official language supports a narrow but useful conclusion: after the $283 Part B deductible, beneficiaries usually pay 20% of the approved cost for covered services and items when the provider accepts assignment. The exception language and service type remain part of a complete reading of that rule.
The State Programs Outside the Bill
Part B coinsurance can continue after the deductible because Medicare Savings Programs are separate, state-run systems rather than automatic credits. Some programs may pay premiums and other Medicare costs, while Extra Help addresses prescription-drug costs.
The Benefits Checklist is a 69-page guide covering 11 programs, with 2026 income limits, a printable tracker and a 50-state phone directory.
Compare the Medicare assistance programs in The Benefits Checklist.
AI tools assisted in researching and drafting this article, which was reviewed prior to publication.
David M. Keller is a finance writer based in Columbus, Ohio, covering personal finance and consumer-focused economic topics. He earned his degree in journalism from Ohio University and began his career reporting on local business and economic trends for a regional media outlet. Since then, he has contributed to a variety of online publications, focusing on clear, practical coverage of topics such as cost of living, debt, and everyday financial decision-making.
