Where to send your Medicare claim depends on what type of service you received

Most claims go to your Medicare Part B carrier — the private insurance company that processes claims for your region. If you received hospital care, the claim goes to a Medicare Administrative Contractor (MAC) instead. Your healthcare provider usually sends the claim for you, but you can also submit it yourself if the provider did not.

The fastest way to find out where your specific claim should go is to call Medicare directly at 1-800-MEDICARE (1-800-633-4227). They can tell you the correct address or online portal for your region in one call. You can also visit Medicare.gov and use their "Find Care Providers" tool to look up your local carrier.

Paper claims and online claims both take roughly the same amount of time to process — usually 10 to 30 days — but online submission means you get a confirmation number when ready and can track the status without calling back.

Key Takeaways

  • Your provider usually files the claim for you automatically, but you can submit it yourself using Form CMS-1500 (paper) or through your carrier's online portal.
  • Medicare Part B claims go to your regional Part B carrier; hospital claims go to your regional Medicare Administrative Contractor (MAC).
  • You can find your carrier's address and submission portal by calling 1-800-MEDICARE or visiting Medicare.gov.
  • Keep copies of your itemized bill, proof of payment, and any correspondence with your provider in case you need to resubmit or appeal.
  • Processing takes 10 to 30 days; you can check the status online or by phone once you have a claim number.

How to submit a claim yourself if your provider did not

Start by gathering your itemized bill from the healthcare provider — this shows each service, the date, and the charge. You will also need your Medicare card (for your Medicare number) and proof that you paid out of pocket, such as a receipt or credit card statement.

If you are submitting on paper, use Form CMS-1500, which you can read free from Medicare.gov or request by calling 1-800-MEDICARE. Fill in your information, your provider's information, and details about the service. Mail it to your regional Part B carrier along with a copy of your itemized bill and proof of payment.

If your carrier offers online submission, log in to their portal (your carrier's website will have a link), upload your bill and proof of payment, and submit. You will receive a confirmation number when ready. Online submission is usually faster because the carrier can process it without waiting for mail delivery.

What information you need before you start

Have these items ready before you contact your carrier or fill out a form:

  • Your Medicare number (on your Medicare card)
  • The date of service
  • The name and address of the healthcare provider or facility
  • The type of service (office visit, lab test, imaging, surgery, etc.)
  • The amount you paid out of pocket
  • A copy of your itemized bill from the provider
  • Proof of payment (receipt, credit card statement, or cancelled check)

If you do not have an itemized bill, call your provider's billing department and ask them to send one. Do not submit a claim with only a credit card charge or a receipt that does not list what service was provided — the carrier will reject it and ask you to resubmit.

Submitting a claim for services you paid for out of pocket

If you paid the full cost of a service at the time of care, you can still file a claim and ask Medicare to reimburse you for the portion it covers. This happens most often when you see an out-of-network provider or when a provider does not accept Medicare assignment.

The process is the same: gather your itemized bill and proof of payment, then submit through your carrier's online portal or by mail. Include a note explaining that you paid out of pocket and are requesting reimbursement. The carrier will review the claim, determine what Medicare covers, and send you a check for that amount.

Reimbursement usually arrives 10 to 30 days after the carrier receives your claim. If you do not receive payment within 45 days, call your carrier to ask for a status update and confirm they received all your documents.

Tracking your claim status and understanding the response

Once you submit a claim, you can check its status online through your carrier's website or by calling your carrier directly. Have your claim number ready — you will receive this number when you submit online, or you can find it on any correspondence from the carrier.

When the carrier processes your claim, they send you an Explanation of Benefits (EOB). This document shows what Medicare paid, what you owe, and why the carrier made those decisions. Read it carefully: it tells you whether the claim was approved, denied, or approved for a different amount than you expected.

If the carrier approved the claim, the payment goes to your provider if they accept Medicare assignment, or to you if you paid out of pocket. If the carrier denied the claim or paid less than you expected, the EOB will explain why. You can then decide whether to appeal.

What to do if your claim is denied or underpaid

If your claim was denied or paid less than you think it should be, you have the right to appeal. The EOB will include instructions for filing an appeal and a important date — usually 120 days from the date on the EOB.

To appeal, write a letter to your carrier explaining why you disagree with their decision. Include a copy of the EOB, a copy of your itemized bill, and any other documents that support your case — such as a letter from your doctor explaining why the service was medically necessary. Mail it to the address listed on the EOB.

Appeals can take 30 to 60 days to process. If you disagree with the appeal decision, you can request a second review, though the process becomes more formal at that stage. For help understanding your appeal options, call 1-800-MEDICARE and ask to speak with a Medicare counselor.

Common reasons claims are delayed or rejected

Claims are most often delayed because the carrier is missing information. The most common missing pieces are an itemized bill (not just a receipt), proof of payment, or your Medicare number. If your claim is rejected for this reason, the carrier will send you a notice explaining what is missing. Gather the missing documents and resubmit.

Claims are rejected for medical reasons when the carrier determines that Medicare does not cover the service — for example, if it was deemed not medically necessary, or if it is a service Medicare does not cover at all. If this happens, the EOB will explain which Medicare rule applies. You can appeal if you believe the decision is wrong.

Claims can also be delayed if your provider submitted it incorrectly or if there is a discrepancy between what your provider billed and what you paid. Call your provider's billing department to ask whether they submitted the claim and, if so, to confirm the amount they billed.

Frequently Asked Questions

Do I have to submit the claim myself, or will my doctor do it?

Most providers submit claims automatically as part of their billing process. Ask your provider's billing office whether they submitted your claim to Medicare. If they did not, you can submit it yourself using the steps above. Some providers do not accept Medicare assignment and will not submit for you — in that case, you must submit the claim yourself to get reimbursed.

How long does it take Medicare to pay a claim?

Most claims are processed within 10 to 30 days of receipt. If you submitted online, processing is usually faster because there is no mail delay. If you have not received payment or a response within 45 days, call your carrier to check the status and confirm they received all your documents.

What if I lost my receipt or proof of payment?

Contact your provider and ask for a copy of your bill and a record of your payment. If you paid by credit card or check, your bank or credit card company can also provide proof. The carrier needs to see that you actually paid before they will reimburse you.

Can I submit a claim for a service from several months ago?

Yes, but there are time limits. You generally have up to one year from the date of service to submit a claim to Medicare. After that, Medicare will not process it. If you are close to the one-year important date, submit as soon as possible.

What if my provider and Medicare disagree about the price?

Medicare has set rates for most services. If your provider charged more than Medicare's rate, you may owe the difference depending on whether they accept Medicare assignment. If you think the charge is wrong, ask your provider to explain it. If you disagree, you can appeal the claim or file a complaint with your state's insurance commissioner.