Most doctors take what Medicare pays and call it a day. A small group does not. They can bill you up to 15% more than Medicare pays, and that extra amount is your problem. It is called a Part B excess charge, and it is one of the small Medicare rules that trips people up.
The short answer
A Part B excess charge is an extra fee a doctor can add on top of what Medicare covers. It is capped at 15% of the Medicare-approved amount. Only a "non-participating" doctor can charge it. If your doctor accepts Medicare assignment (most do), you never see the fee. If they do not, you owe the difference unless your Medigap plan covers it.
Plan G and Plan F cover excess charges. Plan N does not. Eight states ban excess charges entirely.
How Medicare Part B pays doctors
Medicare sets an approved amount for each service. That amount is called the Medicare fee schedule. Say a routine office visit has an approved amount of $100.
Here is how the money splits up in a normal situation:
- Medicare pays 80%, or $80
- You pay 20%, or $20 (after your Part B deductible)
- Total the doctor gets: $100
That is what happens when the doctor accepts Medicare assignment. "Assignment" just means the doctor agrees to accept the Medicare-approved amount as full payment. About 96% of doctors do this. It is the default.
What happens with a non-participating doctor
Some doctors sign up with Medicare but choose NOT to accept assignment. They are called "non-participating" providers. They can bill you more than the Medicare-approved amount.
The catch is Medicare limits how much more. The most they can charge is 15% above what Medicare allows. That extra amount is the Part B excess charge.
Here is the same $100 visit with a non-participating doctor:
- Medicare-approved amount: $100
- Doctor's limiting charge: $115 (Medicare-approved amount plus 15%)
- Medicare pays 80% of $95 (not $100, because of a small extra rule), which is $76
- You pay the rest: $39 out of pocket
You just paid $39 instead of $20 for the same visit. That is the excess charge in action.
Who charges excess fees?
Non-participating providers are the minority. But they exist in certain specialties more than others. Fields where excess charges pop up more often:
- Some private-practice specialists (dermatology, ophthalmology, orthopedics)
- Concierge doctors and boutique practices
- Certain surgeons in urban areas
- Some mental health providers
Primary care doctors almost never charge excess fees. Most hospital-employed doctors also accept assignment as a rule of their contract.
The three types of Medicare providers
To keep it straight, Medicare providers fall into three groups:
| Type | Accepts Assignment? | Can Charge Excess? |
|---|---|---|
| Participating | Yes, always | No |
| Non-participating | Only case-by-case | Yes, up to 15% |
| Opt-out | Not enrolled in Medicare | Charges whatever they want; you pay 100% |
Opt-out providers are a separate problem. They have signed a private contract with you and are not billing Medicare at all. You pay everything yourself, and Medicare pays nothing. That is not an excess charge situation. That is a full private-pay situation.
How to know before you book
Ask this one question when you call a new doctor's office: "Do you accept Medicare assignment?"
Three possible answers:
- "Yes, we accept assignment." Great. No excess charges. You pay only your normal 20% coinsurance.
- "We are non-participating." Ask what percentage they charge above Medicare. Usually 15% (the max). You will owe more.
- "We do not take Medicare / we are private-pay only." That is opt-out. Medicare pays zero. You cover everything.
You can also look up any provider using Medicare's Care Compare tool. The listing shows whether they accept assignment.
The eight states that ban excess charges
Some states passed laws that block excess charges entirely, no matter what. These states are:
- Connecticut
- Massachusetts
- Minnesota
- New York
- Ohio
- Pennsylvania
- Rhode Island
- Vermont
If you live in one of these states, you cannot be charged an excess fee. The doctor must accept the Medicare-approved amount even if they are technically non-participating. This is state law, not federal.
Two of my licensed states, Ohio and Pennsylvania, are on that list. If you are reading this from OH or PA, this article matters less to you directly, but it still helps if you travel or use out-of-state specialists.
How Medigap plans handle excess charges
This is where Medigap earns its keep. A Medigap plan can cover Part B excess charges so you never see the extra bill.
| Medigap Plan | Covers Excess Charges? |
|---|---|
| Plan F (grandfathered) | Yes, 100% |
| Plan G | Yes, 100% |
| Plan N | No |
| Plan A | No |
| High-Deductible Plan G | Yes, after deductible |
Plan G is the most popular Medigap plan sold today. Its coverage of excess charges is one small reason it wins over Plan N for people who care about zero surprises. See our full Plan G vs Plan N comparison.
What about Medicare Advantage?
Medicare Advantage plans work totally differently. Excess charges do not apply the same way. Advantage plans set their own copays and coinsurance in exchange for network rules. You pay the plan's copay, not a Medicare percentage.
The catch with Advantage: if you go OUT of network on a PPO plan, you can face much higher costs than a 15% excess. And HMO plans do not cover out-of-network at all except in emergencies. Different problem, same theme: know your provider status before you go.
Why some doctors go non-participating
You might wonder why any doctor would choose to be non-participating. It seems like a lose-lose. Fewer patients want to book with you, and the paperwork is slightly harder.
The reasons doctors give:
- They believe Medicare's fee schedule undervalues their specialty
- They serve a private-pay-heavy patient mix and want flexibility
- They are in a solo or small practice with high overhead
- They are transitioning toward opting out of Medicare entirely
It is legal, but the trend has been toward more assignment acceptance over the last decade. Federal reporting shows over 96% of physicians accepting assignment on all claims. The 4% or so that do not are shrinking.
What the Medicare Summary Notice shows
Your Medicare Summary Notice (MSN) arrives every three months if you have any Part A or Part B claims. It shows:
- The service the doctor billed
- The amount the doctor charged
- The Medicare-approved amount
- What Medicare paid
- What you may owe the provider
Look at the "amount charged" vs "Medicare-approved amount" columns. If they match, the provider accepted assignment. If the charged amount is higher, you may have paid an excess charge.
If you use MyMedicare.gov, you can see claims in real time instead of waiting for the paper notice.
Real-world example: knee surgery
An orthopedic surgeon is non-participating. The Medicare-approved amount for the surgery is $2,500.
Without excess charges (participating surgeon):
- You owe 20%, or $500
- Medigap Plan G pays that $500
- Your out-of-pocket: $0
With excess charges and Plan N (no excess coverage):
- Surgeon's limiting charge: $2,875 (15% over)
- Medicare pays about $1,900
- You owe the difference: about $975
- Plan N covers standard 20% coinsurance but NOT the $375 excess
- Your out-of-pocket: $375 plus the $20 copay
Not the end of the world, but not fun either. A quick call to ask about assignment would have avoided it.
Common mistakes
Assuming every doctor takes assignment
Most do. Not all. Specialists are the ones to check on. Never assume.
Confusing "accepts Medicare" with "accepts assignment"
These are different. A doctor who "accepts Medicare" might be non-participating and still charge excess. Ask about assignment specifically.
Picking Plan N without thinking about excess
Plan N is cheaper than Plan G but does not cover excess charges. That is fine if you live in a ban state or use participating doctors. Not fine if you plan to see a non-participating specialist regularly.
Not reading the MSN
Your Medicare Summary Notice shows exactly what Medicare paid, what the doctor charged, and what you owe. If you see a bigger balance than expected, check for an excess charge.
The bottom line
Part B excess charges are a small but real gotcha for people on Original Medicare. Most doctors take assignment and never charge extra. A few do not, and you can owe up to 15% more.
Three ways to protect yourself: ask every new doctor about assignment before you book, pick Medigap Plan G if you want the excess-charge protection built in, and use Medicare.gov Care Compare to verify a provider's status.
Not sure whether Plan G, Plan N, or something else fits you best? See how Medigap carriers compare or what Medicare really costs in 2026. Or book a free call and we will walk through your situation together.
Frequently asked questions
What is a Medicare Part B excess charge?
An extra fee a non-participating doctor can charge on top of the Medicare-approved amount, capped at 15%. Doctors who accept assignment do not charge it.
How much is the Medicare Part B excess charge?
Up to 15% above what Medicare approves. On a $200 visit that is up to $30 extra. Adds up quickly if you see specialists often.
How do I know if a doctor charges Part B excess charges?
Ask the front desk one question: "Do you accept Medicare assignment?" Yes means no excess. Non-participating means you may owe more. You can also check Medicare.gov Care Compare.
Does Medigap cover Part B excess charges?
Plan G and Plan F cover excess charges in full. Plan N does not. If you want no surprises, Plan G is the safer choice.
Are Part B excess charges banned in some states?
Yes. Eight states ban them: Connecticut, Massachusetts, Minnesota, New York, Ohio, Pennsylvania, Rhode Island, and Vermont. Non-participating doctors in those states cannot bill excess amounts.