The Short Version
- The current form is the CMS-1500 (02/12), printed in red ink so payers can scan it.
- The official instructions come from the National Uniform Claim Committee (NUCC). The current manual is version 13.0, July 2025.
- Payers can add their own rules for some boxes. When they do, the payer's instructions come first.
- Medicare requires electronic claims from most providers. The electronic claim is the 837P, and every box below has a matching 837P field.
Patient and Insurance Boxes (1 to 13)
| Box | What goes there | Watch out for |
|---|---|---|
| 1 | Type of coverage (Medicare, Medicaid, TRICARE, group plan and so on) | Mark only one box |
| 1a | Insured's ID exactly as on the card | For TRICARE, the 11-digit DoD benefits number |
| 2 | Patient name: last, first, middle initial | No titles such as Dr or Jr after the first name |
| 3 | Patient birth date (8 digits) and sex | Must match the payer's records |
| 4 | Insured's name | Same person as box 1a |
| 5 | Patient address | No punctuation; ZIP code without a hyphen |
| 6 | Patient relationship to the insured | Self, spouse, child or other |
| 7 | Insured's address | Fill when box 4 is filled |
| 8 | Reserved for NUCC use | Leave blank |
| 9, 9a, 9d | Other insured's name, policy number and plan name | Fill only if box 11d is Yes |
| 9b, 9c | Reserved for NUCC use | Leave blank |
| 10a to 10c | Is the condition related to employment, an auto accident (with state) or another accident? | A Yes can send the claim to coordination of benefits review |
| 10d | Claim codes set by NUCC | Only when your payer asks for them |
| 11 | Insured's policy or group number | No hyphens or spaces |
| 11a to 11d | Insured birth date, other claim ID, plan name, other plan? | 11d must be answered if there is other coverage |
| 12 | Patient signature: "Signature on File" or SOF | Release of information |
| 13 | Insured signature: SOF | Authorizes payment to the provider |
Dates, Referring Provider and Claim Details (14 to 23)
| Box | What goes there | Watch out for |
|---|---|---|
| 14 | Date of current illness, injury or pregnancy | Qualifier 431 (onset) or 484 (last menstrual period) |
| 15 | Other date | Qualifiers such as 454 (initial treatment), 304 (latest visit) or 439 (accident) |
| 16 | Dates the patient could not work | Mainly workers' compensation and disability |
| 17 | Referring, ordering or supervising provider | Qualifier DN (referring), DK (ordering) or DQ (supervising); NPI in 17b |
| 18 | Hospital admission and discharge dates | For services tied to a hospital stay |
| 19 | Additional claim information | Payer-specific; use the NUCC qualifiers |
| 20 | Outside lab and its charges | Yes means another entity did the service |
| 21 | ICD indicator and up to 12 diagnosis codes (A to L) | Indicator 0 for ICD-10-CM; no decimal points |
| 22 | Resubmission code and original reference number | Only for corrected (7) or voided (8) claims |
| 23 | Prior authorization, referral, CLIA or mammography number | No hyphens or spaces |
Box 22 causes more rejections than any other. Our claim frequency code tool tells you which code to use, and our guide to filing a corrected claim explains the process.
Service Lines (24A to 24J)
| Box | What goes there | Watch out for |
|---|---|---|
| 24A | Dates of service, from and to | The shaded area above holds extra details, such as the NDC with qualifier N4 |
| 24B | Place of service code | Two digits; see our POS code guides |
| 24C | Emergency indicator | Only if your payer asks; Y or blank |
| 24D | CPT or HCPCS code and up to four modifiers | No descriptions; see our modifier guides |
| 24E | Diagnosis pointer: the letters from box 21 | Letters, not codes; primary first; up to four |
| 24F | Charge for the line | No dollar signs or commas |
| 24G | Days or units | Enter 1 for a single service; anesthesia in minutes |
| 24H | EPSDT or family planning | Mainly Medicaid |
| 24I | ID qualifier for a non-NPI number | Shaded area only |
| 24J | Rendering provider NPI (unshaded) or other ID (shaded) | Fill when it differs from the billing provider in box 33 |
For drugs, the NDC goes in the shaded part of 24A. Our NDC units calculator builds that line for you.
Provider and Billing Boxes (25 to 33)
| Box | What goes there | Watch out for |
|---|---|---|
| 25 | Federal tax ID of the billing provider (EIN or SSN) | Mark which one it is |
| 26 | Patient account number from your system | Comes back on the remittance, so make it useful |
| 27 | Accept assignment? | Answer for all payers |
| 28 | Total charge | Must equal the sum of 24F |
| 29 | Amount paid by the patient or other payers | Covered services only |
| 30 | Reserved for NUCC use | Leave blank |
| 31 | Signature of the physician or supplier, with date | SOF is accepted |
| 32, 32a | Service facility name, address and NPI | Use only when the service was at an outside facility |
| 33, 33a | Billing provider name, address, phone and NPI | Always required; 9-digit ZIP code without a hyphen |
Where Each Box Lives in the 837P
If you bill electronically, your software builds an 837P from the same data. When a clearinghouse rejects a claim, it often names the 837P field, not the box. This table maps the boxes that cause the most trouble:
| Box | 837P location |
|---|---|
| 1a Insured's ID | Loop 2010BA, NM109 |
| 21 Diagnosis codes | Loop 2300, HI segment |
| 22 Resubmission code and original claim number | Loop 2300, CLM05-3 and REF*F8 |
| 23 Prior authorization or referral number | Loop 2300, REF*G1 (prior authorization) or REF*9F (referral) |
| 24A Date of service | Loop 2400, DTP*472 |
| 24B Place of service | Loop 2300, CLM05-1 (or 2400, SV105 if a line differs) |
| 24D Procedure code and modifiers | Loop 2400, SV101 |
| 24E Diagnosis pointer | Loop 2400, SV107 |
| 24F Line charge | Loop 2400, SV102 |
| 24G Units | Loop 2400, SV104 |
| 24J Rendering provider | Loop 2310B (or 2420A if a line differs) |
| 25 Tax ID | Loop 2010AA, REF*EI |
| 26 Patient account number | Loop 2300, CLM01 |
| 28 Total charge | Loop 2300, CLM02 |
| 32 Service facility | Loop 2310C |
| 33 Billing provider | Loop 2010AA |
The 10 Mistakes Behind Most Rejections
- Decimal points in ICD-10 codes in box 21.
- Diagnosis codes in box 24E instead of the letters A to L.
- Box 22 filled in on an original claim, or left blank on a corrected one.
- No qualifier in box 14, 15 or 17.
- Blank units in box 24G.
- A group practice leaving 24J blank when the payer needs the individual rendering NPI.
- A 5-digit ZIP code in box 33 when the payer needs all 9 digits.
- A name, birth date or ID that does not match the card exactly. That leads to CO-31.
- Photocopied or black-and-white forms that the payer's scanner cannot read.
- A missing NDC in the shaded part of 24A for drug lines.
Paper or Electronic?
Medicare requires most providers to bill electronically. Small providers with fewer than 10 full-time employees can qualify for an exception. Medicaid and commercial payers still take paper, but it is slower and easier to get wrong. A clearinghouse turns the same data into an 837P and catches many of the errors above before the payer sees them.
Sources: NUCC 1500 Health Insurance Claim Form Reference Instruction Manual, version 13.0 (July 2025); NUCC 1500 FAQs; ASC X12 005010X222A1 (837 Professional) implementation guide.
Frequently Asked Questions
What is the CMS-1500 form used for?
The CMS-1500 is the standard paper claim form for professional services, such as physician, therapy and supplier claims. Hospitals use the UB-04 instead. Most claims are now sent electronically as an 837P, which carries the same information.
What goes in box 22 on the CMS-1500?
Box 22 is only for resubmitted claims. Put the frequency code on the left (7 to replace a claim, 8 to void it) and the payer's original claim number on the right. Leave it blank on an original claim.
What goes in box 24J?
Box 24J holds the rendering provider's ID. The NPI goes in the white (unshaded) part and any other ID goes in the shaded part. NUCC says to fill it only when it differs from the billing provider in box 33.
What is the difference between box 32 and box 33?
Box 32 is where the service was given, such as a hospital or outside facility. Box 33 is the billing provider who gets paid, with its address, phone number and NPI in 33a.
Do you use decimals in ICD-10 codes on the CMS-1500?
No. The NUCC manual says not to include the decimal point in box 21, because it is implied. Enter up to 12 codes on lines A to L and use the ICD indicator 0 for ICD-10-CM.
Reviewed by Hassan Raza Awan, Founder — 4+ years of hands-on U.S. medical billing experience. General billing information — verify against current CMS guidance and your payer contracts.
Check a filled claim with our CMS-1500 claim checker. Billing for a facility? See our UB-04 form instructions. Check the filing deadline before you send with our timely filing calculator.
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