Check your CMS-1500 before you send it
Catches the formatting and consistency errors payers reject — and nothing you type ever leaves your browser. Free, no account, no upload.
Last reviewed against the NUCC 1500 Reference Instruction Manual (v13.0 7/25) and CMS Pub 100-04 Ch. 26 on .
Your claim data never leaves this browser
Everything you type into the claim checker is checked on your own computer. Nothing is uploaded, stored, or sent to us — we never see it, and there is nothing for us to lose. Close the tab and it's gone. You can verify this yourself: open your browser's network tab and watch that nothing is sent while you type.
See the privacy page for the full statement.
What this checks
Format and completeness
Eight-digit patient DOB in box 3, 9-digit ZIP in boxes 32 and 33, ICD indicator in box 21, NPI check digits — the mundane defects that return a claim before anyone looks at the medicine.
Cross-box consistency
A diagnosis pointer in 24E that points to a letter you never filled in at 21. Box 28 that does not equal the sum of 24F. Box 6 set to Self while boxes 2 and 4 disagree.
Known rejection triggers
Reserved boxes that still get filled, commas in diagnosis pointers, decimals in ICD codes, and Medicare-specific rules when you select that payer profile.
Paste an NPI and we’ll check it
Runs entirely in your browser. A valid check digit does not mean the NPI is active or enrolled — only that the number is well-formed.
That’s one of 40+ checks — run a full claim →
What is the CMS-1500?
The CMS-1500 is the standard paper claim form used by non-institutional providers to bill professional services to Medicare, Medicaid, TRICARE, CHAMPVA, and commercial payers. It has 33 numbered boxes covering patient, insured, provider, diagnosis, and service-line information.
The current form version is 02/12. It received OMB approval in 2013, payers began accepting it in January 2014, and it became the only accepted version on 1 April 2014. It has not been revised since. The instruction manual is revised more often — this site pins rules to NUCC manual 13.0 7/25.
Its electronic sibling is the ANSI ASC X12N 837 Professional (837P) transaction. This site checks the paper form; it does not generate 837P files. See 837P explained.
Paper claims are not obsolete. Medicare requires electronic submission for most providers under the Administrative Simplification Compliance Act, with a small-provider exception (and other limited exceptions). Many Medicaid, TRICARE, and commercial claims still move on the 1500. This tool is for people who still fill the form and want it checked before it bounces.
Common reasons claims come back
Full catalogue with codes and fixes: [Why claims get rejected](/rejections). Ranked counts below are from one Medicare contractor (CGS Jurisdiction 15 — Kentucky and Ohio only), not a national ranking.
Explore
Check a claim
Field-by-field checker. Free, private, no signup.
Box-by-box instructions
What goes in boxes 1–33, format examples, and what gets each rejected.
Rejection catalogue
Returned as unprocessable vs denied, and how to fix the form.
Blank form
Where to get official OCR-red stock — and why a black-and-white printout often fails.
HCFA-1500
Same form, old name. What to send when a payer still says HCFA.
837P
The electronic equivalent of the paper form — and why this site does not generate one.
Common questions
- Is it free?
- Yes, completely, with no account and no limit. There is no paid plan.
- Is my patient data safe?
- Everything you type into the claim checker stays in your browser. Nothing is uploaded, stored, or sent to us. See the privacy page for how to verify that in your network tab.
- Which version of the form does this check?
- Version 02/12, the current CMS-1500 since 1 April 2014, against NUCC instruction manual version 13.0 7/25.
- Will this guarantee my claim gets paid?
- No. We check formatting, completeness, and consistency between boxes against published completion rules. We cannot see eligibility, coverage, medical necessity, or payer-specific edits. A clean result means we found nothing wrong with the form — not that the claim will be accepted or paid.
- Does it submit my claim to the payer?
- No. It checks what you have filled in. You still submit the claim the way you do now — on official stock, through a clearinghouse, or via your practice-management system.
- What's the difference between the CMS-1500 and the HCFA-1500?
- They are the same form. The Health Care Financing Administration was renamed the Centers for Medicare & Medicaid Services in 2001, and the form name followed. If a payer asks for a HCFA-1500, send a CMS-1500 (version 02/12).
Found a rule we got wrong?
Tell us which box and which rule ID (from the checker findings). Do not send patient data — we do not need it and should not receive it.
Get in touch
Sources
- NUCC 1500 Health Insurance Claim Form Reference Instruction Manual, Version 13.0 7/25 (opens in a new tab) — National Uniform Claim Committee
- 1500 Claim Form (version 02/12) (opens in a new tab) — National Uniform Claim Committee
- Medicare Claims Processing Manual, Chapter 26 (Pub 100-04) (opens in a new tab) — Centers for Medicare & Medicaid Services
- CMS-1500 paper claim form (OCR red ink and scale requirements) (opens in a new tab) — Centers for Medicare & Medicaid Services
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.