Medical Billing Resource

CMS-1500 Box-by-Box Guide

Browse the CMS-1500 form field by field. Open any box for a focused explanation, review checklist, related boxes and official reference links.

Reviewed September 2026 · Educational reference — verify payer and program requirements.

Jump to a CMS-1500 box

Each page explains the field's general purpose, what to verify, common relationships to other boxes, and where to find official instructions.

Box	Field	What it reports
1	Insurance type	Identifies the type of health coverage shown at the top of the claim, such as Medicare, Medicaid, TRICARE, CHAMPVA, group health plan, FECA, or other coverage.
1a	Insured's ID number	Reports the insured or subscriber identification number used by the health plan.
2	Patient's name	Reports the patient's last name, first name, and middle initial as required by the form.
3	Patient birth date / sex	Reports the patient's date of birth and the sex indicator used on the claim form.
4	Insured's name	Identifies the insured/subscriber when that person differs from the patient.
5	Patient address	Reports the patient's street address, city, state, ZIP code, and telephone number fields on the form.
6	Patient relationship to insured	Shows how the patient is related to the insured/subscriber.
7	Insured's address	Reports the insured/subscriber address information.
8	Reserved for NUCC use	Box 8 on the CMS-1500 (02/12) is reserved for NUCC use.
9	Other insured's name	Used when other health coverage information applies to the claim.
9a	Other insured policy/group number	Reports the policy or group number for other applicable coverage.
9b	Reserved for NUCC use	This subfield is reserved for NUCC use on the 02/12 CMS-1500 form.
9c	Reserved for NUCC use	This subfield is reserved for NUCC use on the 02/12 CMS-1500 form.
9d	Other insurance plan/program name	Identifies the other insurance plan or program when applicable.
10	Condition related to employment/accident	Boxes 10a-10c indicate whether the condition is related to employment, an auto accident, or another accident; 10d is used for claim codes when applicable.
10d	Claim codes / designated use	This area is used for claim codes when required under current NUCC or payer instructions.
11	Insured policy/group/FECA number	Reports the insured's policy, group, or FECA number as applicable.
11a	Insured birth date / sex	Reports the insured's date of birth and sex indicator when required.
11b	Other Claim ID	Used for an Other Claim ID when required under current NUCC/payer instructions.
11c	Insurance plan/program name	Reports the insurance plan or program name associated with the insured.
11d	Another health benefit plan	Indicates whether another health benefit plan may apply.
12	Patient/authorized person signature	Contains the patient's or authorized person's signature authorization related to release of information.
13	Insured/authorized person signature	Contains the insured's or authorized person's authorization related to payment of benefits when applicable.
14	Date of current illness, injury, or pregnancy	Reports the applicable date associated with the current illness, injury, or pregnancy and the qualifier required by current instructions.
15	Other date	Reports another relevant date and qualifier when required.
16	Dates patient unable to work	Reports the from/to dates when the patient is unable to work in the current occupation when applicable.
17	Referring provider or other source	Identifies a referring, ordering, or supervising provider/other source when applicable, along with the appropriate qualifier.
17a	Other ID for referring provider	Reports a non-NPI identifier for the provider in Box 17 when required.
17b	NPI for referring provider	Reports the NPI associated with the provider identified in Box 17 when required.
18	Hospitalization dates	Reports related hospitalization from/to dates when applicable to the claim.
19	Additional claim information	Used for designated additional claim information when required by NUCC or a payer/program.
20	Outside lab / charges	Indicates whether an outside laboratory was used and reports associated charges when applicable.
21	Diagnosis or nature of illness/injury	Lists diagnosis codes that provide clinical context for the claim. The 02/12 form provides diagnosis positions A-L and an ICD indicator.
22	Resubmission code / original reference number	Used for corrected, replacement, or other resubmitted claims when required.
23	Prior authorization number	Reports a prior authorization, referral, or other applicable number when required.
24A	Date(s) of service	Reports the from/to date of service for each service line.
24B	Place of service	Reports the place-of-service code for the setting in which the service was furnished.
24C	EMG	Used for an emergency indicator when required.
24D	Procedures, services, supplies / modifiers	Reports CPT/HCPCS procedure or service codes and applicable modifiers for the service line.
24E	Diagnosis pointer	Links the service line to diagnosis positions listed in Box 21. The pointer references letters such as A, B, C, or D rather than retyping the diagnosis code.
24F	Charges	Reports the charge for the service line.
24G	Days or units	Reports the number of days or units associated with the service line.
24H	EPSDT / family plan	Used for EPSDT/family-plan information when applicable.
24I	ID qualifier	Reports the qualifier for the non-NPI rendering-provider identifier in Box 24J when applicable.
24J	Rendering provider ID / NPI	Reports rendering-provider identification for the service line, including the NPI in the appropriate portion when required.
25	Federal Tax ID number	Reports the billing entity's federal tax identification number and indicates SSN or EIN as applicable.
26	Patient account number	Provides the submitter's patient account or internal control number.
27	Accept assignment	Indicates whether assignment is accepted when applicable.
28	Total charge	Reports the total charge for the claim.
29	Amount paid	Reports the amount already paid on the claim when applicable.
30	Reserved for NUCC use	Box 30 on the CMS-1500 (02/12) is reserved for NUCC use.
31	Provider/supplier signature and date	Contains the physician or supplier signature area, including degrees/credentials as applicable, and the date field shown on the form.
32	Service facility location information	Reports the name and address of the facility/location where services were rendered when required.
32a	Service facility NPI	Reports the NPI for the service facility location when required.
32b	Service facility other ID	Reports another service-facility identifier with the required qualifier when applicable.
33	Billing provider information	Reports billing provider/supplier name, address, ZIP code, and telephone information.
33a	Billing provider NPI	Reports the billing provider's NPI.
33b	Billing provider other ID	Reports another billing-provider identifier with the required qualifier when applicable.

Use payer instructions. A box may be required, situational, or unused depending on the payer, program, provider type and claim. This guide is a workflow reference, not a substitute for the NUCC manual or payer edits.