How to Fill Out a Medicare Claim Form

Insurance claim form representing how to fill them out.

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There are 33 boxes on a Medicare Claim form. That doesn’t include any sub-boxes, which if included, would bring the total closer to 50! That’s a bit overwhelming.

Let’s break these boxes down and explain what is required when filling out a claim form. It’s important these forms are completed accurately so that a timely payment can be made back to you.

Where can I get a claim form?

The proper name for a Medicare claim form is a CMS-1500 Form. 

Usually, you can find this form on your carrier’s website. also has one that you can download and either fill in with a pen or fill in digitally using a PDF editor.

Filling Out the Form: Box by Box

If you choose to fill this form out by hand, make sure that everything is neat and legible. If a claim cannot be read, Medicare won’t come asking for another one! It is up to you to make sure that everything on the form can be easily read by others.

Box 1: This is where you check what type of insurance you have. If you’re reading this article because you have Medicare, then you’ll choose the box that says “Medicare.”

Box 1a: This is where you will neatly write (or type) your Medicare ID number.

Box 2: Write your name exactly as it appears on your Medicare ID card. One extra space or an extra period is enough to get your claim rejected.

Box 3: Enter your date of birth using two digits for the month, two digits for the day, and four digits for the year. Mark male or female to indicate your gender. Do not mark both.

Box 4: If Medicare is the primary payer, this box can be left blank. If Medicare is the secondary payer, enter the name of the other policyholder. If you are the policyholder, you may write “same.”

Box 5: Enter your mailing address and telephone number. Be sure to use your mailing address if it is different than your physical address.

Box 6: If Medicare is the primary payer, this box can be left blank. If there is a different primary payer, mark your relationship to that policyholder.

Box 7: If you completed boxes four, six, and eleven, you will also need to complete this box. Write the primary policyholder’s mailing address and date of birth. If the policyholder and the patient reside together, you may write “same.”

Box 8: Hooray! Nothing for you to do here. Leave this box blank.

Box 9: This box is only filled out if the patient has a Medigap policy. If there is a Medigap policy, enter the last name, first name, and middle initial of the policyholder. If the policyholder is the same as the patient, you may write “same.”

Box 9a: Again, only fill this out if there is a Medigap policy for the patient. Write the words “MG”, “MGAP,” or “MEDIGAP” followed by the policy number and/or group number.

Boxes 9b and 9c: Leave these blank.

Box 9d: Enter the Medigap carrier’s Payer ID. This can usually be found on your policy ID card. If not, use the phone numbers provided on your card to speak with a representative and get this information.

Boxes 10a – 10c: If the claim is due to employment, an auto accident, or other type of accident, check the appropriate box here. If it was due to an auto accident, type the two-letter abbreviation for the state in which the accident occured.

Box 10d: Leave this box empty unless you are filing with Medicaid.

Box 11: If Medicare is the primary payer, simply enter “NONE” in box 11. You cannot leave this box empty. If Medicare is the secondary payer, write the appropriate policy number in box 11, then fill out boxes 11a, 11b, and 11c. Box 11d is not required.

Box 12: Sign and date the form here. Use two digits for the month, two digits for the day, and four digits for the year.

Box 13: Sign here again.

Box 14: If this claim is for a current illness, write in when the illness occurred. 

Box 15: Leave blank.

Box 16: If the patient is currently employed and unable to work, fill in the dates here.

Senior couple filling out a medicare claim form.
Let’s break these boxes down and explain what is required when filling out a claim form.

Box 17: Enter the name of the referring or treating physician.

Box 17a: Leave blank.

Box 17b: Enter the physician’s NPI. You may need to call the physician’s office to obtain this information.

Box 18: Enter the date that a service was provided if hospitalization occurred. 

Box 19: This box can get a little tricky. Again, you may need to speak to your physician’s office for help here as this will depend on what service was provided. If there was testing done for a hearing aid, you could write “testing for hearing aid.” 

Box 20: If someone other than the billing entity purchased testing equipment for the service, mark “yes” and write in the purchase price. Otherwise, mark “no.”

Box 21: ICD-10 diagnosis codes go here. This code is used to diagnose the condition being treated. Ask your physician’s office for this information.

Box 22: Leave blank.

Box 23: If a pre-authorization was filed, fill in the claim number for that authorization here.

Box 24: This box is divided into ten columns and six rows. You may not need to use all 6 rows.

Box 24a: Write in the date of servic

Box 24b: This is the code that designates where the service took place. You will need to look up these codes in the Medicare Claims Processing Manual provided by

Box 24c: Leave blank.

Box 24d: Enter the codes for the services rendered. Ask your physician’s office for this information.

Box 24e: Enter the codes you found for box 21. Enter only one code per line.

Box 24f: Enter the full amount charged for each service code.

Box 24g: Enter how many days the service took place.

Box 24h: Leave blank

Box 24j: Enter the NPI of the provider who rendered the service.

Box 25: Enter the provider’s TID (Tax ID).

Box 26: This item is not required.

Box 27: If the provider accepts Medicare assignment, mark “yes.” If not, mark “no.”

Box 28: Enter the total charges for all services.

Box 29: Enter the total amount that the patient has paid for services.

Box 30: Leave blank.

Box 31: The signature of the physician goes here.

Box 32: Enter the name and address of the facility where services were rendered.

Box 32a: Enter the NPI of the facility. This is different than the physician’s NPI.

Box 32b: If required, enter the PIN of the facility.

Box 33: Enter the provider’s phone number and address.

Box 33a: Enter the provider’s NPI.

Box 33b: Leave blank.


Congrats! You’ve completed the entire Medicare claim form. Make a copy of this form for your own records prior to submitting it to Medicare.

If you are still having trouble, one of our consultants can help you if you request a meeting here.

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Justin Brock

President & CEO of Bobby Brock Insurance