The Basic Rule: Participating vs. Non-Participating Doctors

Whether a doctor can charge you more than Medicare's allowance depends on one thing: whether they have signed a contract with Medicare. A participating provider has agreed to accept Medicare's approved amount as full payment — they cannot bill you the difference. A non-participating provider has not signed that contract and can charge more, but only up to a legal limit called the limiting charge.

The limiting charge is set by law at 115 percent of Medicare's approved amount. So if Medicare approves $100 for a service, a non-participating doctor can charge you up to $115. You pay the difference between what Medicare pays and what the doctor charges, up to that 115 percent cap.

Participating providers are listed in the Medicare provider search tool on Medicare.gov. If you are unsure whether your doctor participates, call their billing office and ask directly — do not assume based on location or reputation.

Key Takeaways

  • Participating doctors cannot charge more than Medicare's approved amount; non-participating doctors can charge up to 115 percent of that amount.
  • The difference between what Medicare pays and what a non-participating doctor charges comes out of your pocket, even after you meet your deductible.
  • Some doctors opt out of Medicare entirely and can charge whatever they want, but they must give you written notice before treatment and cannot bill Medicare at all.
  • You can check whether a doctor participates in Medicare through the Medicare provider search tool before your visit.
  • If a doctor charges more than the limiting charge allows, you can report it to Medicare and may be owed a refund.

How the Limiting Charge Works in Practice

The limiting charge applies only to non-participating providers. Here is how the math works: Medicare approves $100 for an office visit. A non-participating doctor can bill you up to $115. Medicare pays its share — usually 80 percent of the approved amount after you meet your deductible, so $80. You owe $35 out of pocket: the $20 difference between the approved amount and what Medicare paid, plus the $15 difference between the approved amount and what the doctor charged.

This matters because the extra $15 does not count toward your out-of-pocket maximum under Original Medicare. Your deductible and coinsurance count, but balance billing above the limiting charge does not. If you see many non-participating doctors, these charges add up quickly.

The limiting charge does not explore to emergency services, certain mental health services, or a few other narrow categories. For those services, non-participating doctors have more flexibility in what they can charge. Your doctor's office should tell you upfront if they are non-participating and what the limiting charge will be for your specific service.

Doctors Who Opt Out of Medicare Entirely

A small number of doctors choose not to participate in Medicare at all. These are called opted-out providers. They can charge you any amount they want, with no limiting charge. However, they must follow strict rules: they cannot bill Medicare for any of their patients, and they must give you a signed agreement before treatment that explains they do not accept Medicare and what you will owe.

If a doctor opts out, you cannot use your Medicare coverage for their services. You pay the full bill yourself, and Medicare will not reimburse you. Some people choose opted-out doctors deliberately because they prefer a different style of care or have a long-standing relationship. If you do, make sure you understand the cost before your first visit.

You can find out whether a doctor has opted out by calling their office or checking the Medicare provider search tool, which flags opted-out providers clearly.

What Happens If a Doctor Overcharges You

If a non-participating doctor charges you more than 115 percent of the Medicare-approved amount, they have violated federal law. You should report this to Medicare and ask for a refund. Contact Medicare at 1-800-MEDICARE or file a complaint through your Medicare.gov account.

When you report an overcharge, have your bill and the Medicare-approved amount ready. You can find the approved amount by logging into your Medicare account and viewing the Explanation of Benefits (EOB) for that service, or by calling Medicare directly. Medicare will investigate and, if the doctor did overcharge, will order them to refund you the excess.

Keep copies of all bills and EOBs. If the doctor refuses to refund you after Medicare orders them to, you can pursue the debt in small claims court, though this is rare — most doctors comply once Medicare notifies them of the violation.

How to Avoid Surprise Charges Before Your Visit

Before you schedule an appointment or procedure, call the doctor's office and ask three things: Do they participate in Medicare? If not, what is the limiting charge for the service you need? And will they send you an estimate in writing?

Write down the answers and ask for them in writing if possible. If the office cannot or will not tell you, that is a red flag. A participating provider should have no problem confirming their status. A non-participating provider should be able to calculate the limiting charge based on the service code.

If you are having a procedure, ask whether the facility (hospital, surgery center, lab) is in-network for your insurance. Sometimes the doctor participates but the facility does not, or vice versa. Both matter for what you will owe.

Medicare Advantage Plans and Limiting Charges

If you have a Medicare Advantage plan instead of Original Medicare, the limiting charge rules are different. Medicare Advantage plans are required to limit what out-of-network doctors can charge you, but the exact limit depends on your plan. Some plans cap it at the limiting charge; others cap it higher or lower.

Check your plan's provider directory and call your plan's customer service before seeing an out-of-network doctor. They can tell you exactly what you will owe. Do not assume the limiting charge applies — it may not under your specific plan.

Frequently Asked Questions

Can a participating doctor ever charge me more than Medicare approves?

No. Participating doctors sign an agreement to accept Medicare's approved amount as full payment. They cannot charge you the difference. The only exception is if you have not met your deductible or owe coinsurance — then you pay your share of the approved amount, not more.

What is the difference between a non-participating doctor and an opted-out doctor?

A non-participating doctor still bills Medicare but can charge you up to 115 percent of the approved amount. An opted-out doctor does not bill Medicare at all and can charge you any amount. Opted-out doctors must give you written notice before treatment; non-participating doctors do not.

If I see a non-participating doctor, does the extra charge count toward my out-of-pocket maximum?

No. Under Original Medicare, only the deductible and coinsurance on the approved amount count toward your out-of-pocket costs. The balance billing above the limiting charge does not. Medicare Advantage plans may have different rules — check your plan documents.

How do I learn about my doctor participates in Medicare?

Use the Medicare provider search tool on Medicare.gov, or call your doctor's office and ask directly. The office staff can tell you when ready whether they are participating, non-participating, or opted out.

What should I do if a doctor charges me more than the limiting charge?

Report it to Medicare at 1-800-MEDICARE or through your Medicare.gov account. Provide your bill and the Medicare-approved amount from your EOB. Medicare will investigate and order a refund if the overcharge is confirmed.