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CMS-1500 App

Independent resource. Not affiliated with CMS, the NUCC, the AMA, or any payer. Claim data stays in your browser.

CMS-1500 claim checker

Check a 02/12 claim against NUCC manual 13.0 7/25. Findings update as you fill boxes. Your patient data never leaves this browser.

Last reviewed against the NUCC 1500 Reference Instruction Manual (v13.0 7/25) and CMS Pub 100-04 Ch. 26 on .

Form version 02/12 · Rules pinned to NUCC manual 13.0 7/25 · As of 2026-07-18

Who are you billing?

Medicare’s instructions differ from the general instructions in several places. Telling us who you’re billing lets us check the right rules instead of guessing. Default is “I’m not sure” (base NUCC rules only).

Payer and insured — boxes 1, 1a, 4, 7, 11
As shown on the insurance card
Medicare: enter NONE if no primary payer
8 digits MMDDYYYY only
9 digits, no hyphen
Usually Y4 — not a date field
Patient — boxes 2, 3, 5, 6, 8
8 digits MMDDYYYY only

8 — Reserved for NUCC use

This field was retired on the 02/12 form. Leave it blank unless your payer told you otherwise.

Other insured — boxes 9, 9a–9d

9b — Reserved for NUCC use

This field was retired on the 02/12 form. Leave it blank unless your payer told you otherwise.

9c — Reserved for NUCC use

This field was retired on the 02/12 form. Leave it blank unless your payer told you otherwise.

Condition and authorisation — boxes 10, 14–16, 19, 20, 22, 23
6 or 8 digits
431 onset · 484 LMP
Medicare: leave blank
7 replacement · 8 void · blank on original
No hyphens or spaces
Referring / ordering / supervising — boxes 17, 17a, 17b
DN referring · DK ordering · DQ supervising
No periods or commas
0B · 1G · G2 · LU (supervising only)
10 digits
Diagnosis — box 21
0 = ICD-10-CM · 9 = ICD-9-CM

Do not include the decimal point. No narrative descriptions. Max 12 codes (A–L).

Service lines — box 24 (six lines)

Procedure codes are checked for format only. CPT descriptions are licensed by the AMA, so we do not include them. The paper form holds six lines — a seventh requires a second claim form.

Service line 1 of 6

Usually MMDDYY
2-digit POS code
Format only — no descriptions
Letters A–L, no commas
No $ or commas
N4/ZZ/DI… no space after qualifier

Service line 2 of 6

Usually MMDDYY
2-digit POS code
Format only — no descriptions
Letters A–L, no commas
No $ or commas
N4/ZZ/DI… no space after qualifier

Service line 3 of 6

Usually MMDDYY
2-digit POS code
Format only — no descriptions
Letters A–L, no commas
No $ or commas
N4/ZZ/DI… no space after qualifier

Service line 4 of 6

Usually MMDDYY
2-digit POS code
Format only — no descriptions
Letters A–L, no commas
No $ or commas
N4/ZZ/DI… no space after qualifier

Service line 5 of 6

Usually MMDDYY
2-digit POS code
Format only — no descriptions
Letters A–L, no commas
No $ or commas
N4/ZZ/DI… no space after qualifier

Service line 6 of 6

Usually MMDDYY
2-digit POS code
Format only — no descriptions
Letters A–L, no commas
No $ or commas
N4/ZZ/DI… no space after qualifier
Billing and totals — boxes 12, 13, 25–33
SOF, Signature on File, or legal signature
Required only with a legal signature
No date field on the 02/12 form
9 digits
No hyphens, max 14
Exactly one choice
Sum of 24F · no $ or commas
6+2 digits max
6, 8, or alphanumeric

30 — Reserved for NUCC use

This field was retired on the 02/12 form. Leave it blank unless your payer told you otherwise.

32 — Service facility

No punctuation · 9-digit ZIP
Only when different from 33a

Box 32b is not to be reported (effective 2008-05-23) — no input is shown.

33 — Billing provider

Taxonomy qualifier on the 1500 is ZZ, not PXC

What this can’t tell you

What this checks: the form itself — whether entries are formatted correctly, whether required boxes are filled, and whether the boxes agree with each other, measured against the published completion instructions.

What this can’t see:

  • Whether a procedure code was valid on the date of service. CPT codes are licensed by the American Medical Association, so we can’t include them. This is worth knowing: it’s one of the most common reasons claims come back.
  • Whether a procedure and modifier combination is allowed. Same reason.
  • Whether the service is covered by this plan, or by this Medicare contractor.
  • Whether the patient was eligible on the date of service.
  • Whether the ordering or referring provider is enrolled in PECOS. That needs a live registry lookup, and looking it up would mean sending your data somewhere. We’d rather not.
  • Whether a CLIA certification is on file for the lab services billed.
  • Whether Medicare is the primary or secondary payer here.
  • Whether the documentation supports the codes billed.
  • Whether the codes are the right codes for what was done — we check format, not clinical accuracy.
  • Whether the NPI is active and belongs to this provider — we check the number’s structure, not the registry.
  • Your payer’s own edits, which vary and are not published.

A clean result means we found nothing wrong with the form. It is not a prediction that the claim will be paid.

Sources for the rule set

Rules are pinned to the NUCC 1500 Reference Instruction Manual, version 13.0 7/25, and CMS Medicare Claims Processing Manual, Chapter 26, with NPI and MBI format specs from CMS. Every finding in the tool carries its source. The public rule list is on the checker panel.

We do not check CPT validity or procedure/modifier combinations — those require AMA-licensed data we do not ship.

Found a rule we got wrong?

Email the rule ID from the finding card. Never include patient names, member IDs, or diagnosis codes in your message.

Get in touch

Or email hello@cms1500.app

Sources

  1. NUCC 1500 Health Insurance Claim Form Reference Instruction Manual, Version 13.0 7/25 (opens in a new tab) — National Uniform Claim Committee
  2. Medicare Claims Processing Manual, Chapter 26 (Pub 100-04) (opens in a new tab) — Centers for Medicare & Medicaid Services
  3. NPI check digit specification (opens in a new tab) — Centers for Medicare & Medicaid Services
  4. Medicare Beneficiary Identifier (MBI) format (opens in a new tab) — Centers for Medicare & Medicaid Services
  5. Place of Service Code Set (opens in a new tab) — Centers for Medicare & Medicaid Services
  6. CPT licensing FAQs (opens in a new tab) — American Medical Association

Last reviewed against the NUCC 1500 Reference Instruction Manual (v13.0 7/25) and CMS Pub 100-04 Ch. 26 on .

cms1500.app is an independent resource operated by AdvancedCare USA Inc. It is not affiliated with, endorsed by, or connected to the Centers for Medicare & Medicaid Services, the National Uniform Claim Committee, the American Medical Association, or any insurance payer. The CMS-1500 form is maintained by the NUCC.

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