ICD-10-CM Code Lookup (FY 2027)

Check any diagnosis code against the official FY 2027 code set from CMS: its title, whether it is valid for reporting, its chapter and the codes below it.

ICD-10-CM code lookup

ICD-10-CM code

Look up

Code set: ICD-10-CM FY 2027, effective October 1, 2026 to September 30, 2027 (CMS files).

Search category titles

WordsSearch

The FY 2027 set used here has 74,879 codes that are valid for reporting, plus 23,524 headers (categories and subcategories), in 1,921 three-character categories and 22 chapters. Search matches category titles; open a category to see every code in it.

How ICD-10-CM codes are built

"ICD-10-CM diagnosis codes are composed of codes with 3, 4, 5, 6 or 7 characters."

ICD-10-CM Official Guidelines, FY 2027

"Characters for categories, subcategories and codes may be either a letter or a number. All categories are 3 characters."

ICD-10-CM Official Guidelines, FY 2027

The first three characters name the category, and the lookup puts a decimal point after them, as in E11.9. Further characters add detail. Some categories need a 7th character, and the guidelines say a code that has an applicable 7th character is considered invalid without it. When a code that requires a 7th character is shorter than 6 characters, the placeholder X fills the gap.

"For reporting purposes only codes are permissible, not categories or subcategories, and any applicable 7th character is required."

ICD-10-CM Official Guidelines, FY 2027

The CMS order file marks each entry as a header or as valid for submission in HIPAA-covered transactions. The lookup shows that flag as "header" or "valid for reporting".

The 22 chapters

Why coders need this

BLS lists using classification systems to assign clinical codes for patients' diagnoses, procedures, medical services, and related information among the typical duties of medical records specialists. The official guidelines describe ICD-10-CM as a morbidity classification published by the United States for classifying diagnoses and reason for visits in all health care settings. This lookup is a quick reference, not a substitute for the full Tabular List, the Alphabetic Index and the official guidelines.

Frequently asked questions

Which ICD-10-CM codes are in effect now?

CMS says the FY 2027 files are for discharges and patient encounters occurring from October 1, 2026 through September 30, 2027. This lookup uses the FY 2027 code descriptions file from CMS.

How many characters does an ICD-10-CM code have?

The official guidelines say ICD-10-CM diagnosis codes are composed of codes with 3, 4, 5, 6 or 7 characters, and that all categories are 3 characters.

What does the X in an ICD-10-CM code mean?

X is a placeholder. The guidelines say that where a placeholder exists, the X must be used for the code to be considered valid, and that a code needing a 7th character but shorter than 6 characters is filled with X.

Why is my code not valid for reporting?

For reporting, only codes are permissible, not categories or subcategories, and any applicable 7th character is required. If the lookup shows "header", pick one of the codes listed under it.

Who has to use ICD-10-CM?

CMS says ICD-10 applies to all parties covered by the Health Insurance Portability and Accountability Act (HIPAA), not just providers who bill Medicare or Medicaid.

Related tools

Sources

1. CMS: ICD-10 codes, FY 2027 files
2. CMS and NCHS: ICD-10-CM Official Guidelines for Coding and Reporting FY 2027 (PDF)
3. CMS: 2027 Code Descriptions in Tabular Order (ZIP)
4. CMS: 2027 Code Tables, Tabular and Index (ZIP)
5. BLS Occupational Outlook Handbook: Medical Records Specialists (last modified August 27, 2026)