Medicare excess charges are rare. About 98% of physicians and practitioners billing Medicare are participating providers, meaning they accept Medicare’s approved amount as payment in full and cannot charge you anything extra beyond your normal deductible and coinsurance. That leaves only a small fraction of doctors who can legally bill above Medicare’s rates, and even then, federal law caps how much extra they can charge.
What Excess Charges Actually Are
When a doctor participates in Medicare, they agree to accept the Medicare-approved amount for every service. If Medicare says a particular office visit is worth $200, that’s the total billable amount, period. Your share is the standard 20% coinsurance (after your Part B deductible), and that’s it.
A non-participating provider works differently. These doctors still accept Medicare patients, but they haven’t signed a participation agreement. On any given claim, they can choose whether to accept Medicare’s approved amount or charge more. That additional amount above Medicare’s rate is the excess charge. Non-participating providers also receive 5% less from Medicare than participating providers do for the same service, which gives them a financial incentive to bill patients for the difference and then some.
The 15% Cap on Extra Billing
Federal law sets a “limiting charge” that restricts how much a non-participating doctor can bill. The maximum is 115% of the Medicare fee schedule amount for non-participating providers. Because non-participating providers are already paid at 95% of the standard rate, the real math works out to about 109.25% of the full participating-provider rate. In practical terms, if the standard Medicare-approved amount for a service is $200, the most a non-participating doctor could charge you is roughly $218.50 total.
Your out-of-pocket exposure from an excess charge on any single service is relatively modest. But if you see non-participating specialists regularly, or need expensive procedures, those extra percentages can add up over a year.
Why Most People Never Encounter Them
The 98% participation rate means the overwhelming majority of Medicare beneficiaries will never see an excess charge on a bill. Doctors have strong reasons to participate: Medicare pays them directly, forwards claims to supplemental insurers automatically, and gives them full appeal rights. Non-participating providers lose those conveniences and accept lower base reimbursement.
The small group of non-participating doctors tends to be concentrated in certain specialties and geographic areas. If you live in a major metro area with many providers, you’re less likely to end up with a non-participating doctor simply because you have more choices. In areas with fewer specialists, the odds go up slightly, though the numbers are still small overall.
Eight States Ban Excess Charges Entirely
If you live in one of eight states, excess charges are not just uncommon but illegal. Connecticut, Massachusetts, Minnesota, New York, Ohio, Pennsylvania, Rhode Island, and Vermont all prohibit doctors from billing Medicare patients above the Medicare-approved amount. In these states, even non-participating providers must accept assignment.
If you live in one of these states, excess charges are essentially a non-issue regardless of which doctor you see or which Medigap plan you carry.
How Medigap Plans Handle Excess Charges
For people in the other 42 states, Medigap (Medicare supplement) plans offer another layer of protection. Two standardized plan types cover 100% of Part B excess charges: Plan F and Plan G. Plan F is no longer available to people who became newly eligible for Medicare after January 1, 2020, so Plan G is the main option for newer enrollees who want this coverage.
All other Medigap plans, including the popular Plan N, do not cover excess charges at all. If you have Plan N and see a non-participating doctor who bills up to the limiting charge, you pay that extra amount out of pocket.
Whether this coverage gap matters depends on your situation. Given that 98% of providers accept assignment, paying a higher premium specifically for excess charge protection may not be worth it for everyone. But if you regularly see a specialist who doesn’t participate in Medicare, or if you want to eliminate the possibility entirely, Plan G removes that risk.
How to Check Before an Appointment
You can look up any provider’s participation status on Medicare’s official provider directory at Medicare.gov. Search for the doctor’s name and look for whether they accept “assignment.” If they do, they cannot bill excess charges for that claim.
You can also simply ask the doctor’s billing office before scheduling. The key question is whether they accept Medicare assignment. A participating provider always accepts assignment. A non-participating provider may accept it on some claims but not others, so it’s worth confirming for the specific service you need. Doctors who have opted out of Medicare entirely are a separate category: they don’t bill Medicare at all, and you pay their full fee yourself under a private contract.
For most Medicare beneficiaries, excess charges are a theoretical concern rather than a practical one. The combination of high physician participation rates, the federal 15% cap, and state-level bans in eight states means very few people actually encounter these charges. But knowing the rules puts you in a position to avoid them entirely.