If you have ever called a doctor's office and asked, "Do you take Medicare?" you may have gotten a less-than-clear answer. That is because there is more than one way a doctor can "take" Medicare — and the difference can show up on your bill. Whether a provider accepts Medicare assignment determines how much you can be charged, who bills Medicare, and whether you may face an extra amount known as an excess charge. Here is how the system generally works in 2026.
The Short Answer
When a provider accepts Medicare assignment, they agree to accept the Medicare-approved amount as full payment for covered services. You owe only your normal cost-sharing — the $283 Part B deductible (2026) if you have not met it yet, plus 20% coinsurance of the approved amount — and the provider bills Medicare directly on your behalf.
The good news is that assignment is overwhelmingly the norm. According to KFF and CMS data, about 98% of physicians who bill Medicare are "participating" providers who accept assignment on all claims, and MedPAC reports that roughly 99.7% of Medicare claims are paid on assignment. Still, the exceptions generally involve higher costs — and in one case, no Medicare payment at all.
The Three Types of Medicare Providers
Doctors and other providers generally fall into one of three categories with Medicare.
1. Participating providers
Participating providers sign an agreement to accept assignment on every Medicare claim. They charge you no more than the Medicare-approved amount, submit claims directly to Medicare, and collect only your deductible and coinsurance. As noted above, this describes about 98% of physicians billing Medicare. If the difference between coinsurance and flat copays is fuzzy, our guide to copays vs. coinsurance walks through it.
2. Non-participating providers
Non-participating providers are enrolled in Medicare but may decide claim by claim whether to accept assignment. Two important rules apply:
- Medicare pays non-participating providers at 95% of the standard fee schedule amount — a 5% reduction.
- If the provider does not accept assignment on a claim, they may bill you up to the limiting charge: 115% of that reduced amount. This extra amount above the Medicare-approved rate is the Part B excess charge.
Because the 15% markup is applied to a rate that has already been cut by 5%, the maximum charge works out to about 9.25% above what a participating provider would receive. A worked example makes it concrete:
- Medicare-approved amount for a participating provider: $100
- Non-participating approved amount (95%): $95
- Maximum allowed charge (115% of $95): $109.25
Non-participating providers who do not accept assignment may also require payment upfront, in which case Medicare reimburses you, the patient, rather than the doctor.
3. Opt-out providers
A small group of doctors — about 1% of physicians, though the share is higher among psychiatrists at roughly 8% — have formally opted out of Medicare. With an opt-out doctor:
- Neither the doctor nor you can bill Medicare for their services
- The limiting charge does not apply — the doctor may set any fee
- You must sign a private contract stating that you accept full financial responsibility and understand that neither Medicare nor a Medigap policy will pay
One exception: emergency or urgent care from an opt-out doctor you have not signed a private contract with can still be billed to Medicare.
Note that excess charges do not apply to ambulance services or durable medical equipment (DME) — those follow separate payment rules. For a refresher on what Part B covers in the first place, see our guide to what Part A and Part B cover.
Eight States Ban Excess Charges
Several states have passed laws — often called Medicare Overcharge Measure (MOM) laws — that prohibit providers from billing excess charges. As of 2026, these states are:
- Connecticut
- Massachusetts
- Minnesota
- New York
- Ohio
- Pennsylvania
- Rhode Island
- Vermont
Two details matter here. First, the protection is generally based on where you receive care, not where you live — an out-of-state visitor treated in Pennsylvania is generally protected, while a Pennsylvania resident treated elsewhere may not be. Second, New York's rule is technically a 5% cap rather than a complete ban. If you split time between states or are planning a move, see our guide to Medicare when you move to a new state.
How Medigap Treats Excess Charges
If you have Original Medicare with a Medicare Supplement policy, coverage for excess charges depends on the plan letter. Only Medigap Plans F and G — including their high-deductible versions — cover Part B excess charges. Plan N does not; our comparison of Medigap Plan G vs Plan N looks at that trade-off in detail. For a broader map of what each standardized plan letter covers, see our Medigap plan comparison guide.
Since the vast majority of claims are paid on assignment, excess charges are uncommon in practice — but they are unpredictable, and whether that risk matters to you may depend on the providers you use and where you receive care.
How to Check a Provider's Status
You do not have to guess. Before an appointment:
- Search Medicare.gov's Care Compare tool, which shows whether a provider accepts assignment
- Ask the office directly: "Do you accept Medicare assignment?" — a more precise question than "Do you take Medicare?"
- If the provider is non-participating, ask whether they will accept assignment for your visit and whether payment is required upfront
How to Get Help and Learn More
If you want to confirm how a specific provider bills Medicare or what you would owe, these official resources can help:
- Medicare.gov — See the official page on doctor and hospital costs at medicare.gov/basics/costs/medicare-costs, and look up providers with the Care Compare tool at medicare.gov/care-compare.
- 1-800-MEDICARE (1-800-633-4227) — Medicare's official helpline can answer assignment and billing questions. TTY users can call 1-877-486-2048.
- State Health Insurance Assistance Program (SHIP) — SHIP offers free, unbiased counseling on provider billing rules and your coverage options. Find your local program at shiphelp.org or by calling 1-800-MEDICARE.
Summary and Next Steps
Medicare assignment sounds like billing jargon, but it directly shapes what you pay. Key points to remember:
- Accepting assignment means the provider takes the Medicare-approved amount as full payment — you owe only the $283 deductible (2026) and 20% coinsurance
- About 98% of physicians billing Medicare participate fully, and 99.7% of claims are paid on assignment
- Non-participating providers who decline assignment may bill up to the limiting charge — effectively about 9.25% above the participating rate — and may require payment upfront
- Opt-out doctors (about 1%) require a private contract; neither Medicare nor Medigap pays, and the limiting charge does not apply
- Eight states ban excess charges (CT, MA, MN, NY, OH, PA, RI, VT), based on where care is received — New York technically caps them at 5%
- Medigap Plans F and G cover excess charges; Plan N does not
Before your next appointment with a new provider, check their status on Care Compare or ask whether they accept assignment. And if a bill ever looks higher than the rules above allow, your local SHIP counselor can review it with you for free.
