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ICD-9 to ICD-10 Converter

Crosswalk legacy ICD-9-CM codes to their current ICD-10-CM equivalents with the official CMS General Equivalence Mappings, including the approximate, combination, and no-map flags coders need to interpret each match.

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Official CMS General Equivalence Mappings Final GEMs release (FY 2018) Maps in both directions

How to Convert

  1. Enter the ICD-9 code, with or without the decimal point: 250.00 and 25000 both work. The autocomplete finds a code from its description too.
  2. Review every candidate. One ICD-9 code often maps to several ICD-10 codes; the crosswalk lists them all, best-known equivalent first.
  3. Read the flags. An unflagged mapping is exact; Approximate, Combination, and No Map each change how the result should be used.
  4. Confirm on the code page. Every mapped code links to its full page with descriptions, categories, and billing status.

Reading the Mapping Flags

  • No flags means an exact equivalent: the source code maps cleanly to the target code without qualification.
  • Approximate means the closest available equivalent, not an exact match; review the documentation before selecting it.
  • Combination means more than one target code is required to express the source code's full meaning.
  • No Map means the source code has no counterpart in the target system at all.

GEMs Conversion FAQ

What are the General Equivalence Mappings (GEMs)?
The GEMs are the official crosswalk between ICD-9-CM and ICD-10-CM, developed by the Centers for Medicare and Medicaid Services (CMS) and the National Center for Health Statistics (NCHS) for the 2015 transition. They map in both directions and remain the standard reference for translating legacy claims, audits, research datasets, and reimbursement logic between the two code sets.
How do I convert an ICD-9 code to ICD-10?
Type the ICD-9 code in the converter, with or without the decimal point, and open the conversion. The autocomplete also finds the code from its description if you do not remember the number. Every ICD-9 and ICD-10 code page on this site links to its conversion as well.
Why does one ICD-9 code convert to several ICD-10 codes?
ICD-10-CM is far more specific: it carries over five times as many diagnosis codes, adding laterality, encounter type, and finer clinical detail. A single ICD-9 code therefore often maps to a family of candidate ICD-10 codes, and the clinical documentation determines which one applies. The crosswalk lists every candidate with its mapping flags.
What do the Approximate, No Map, and Combination flags mean?
Approximate means the target code is the closest available equivalent rather than an exact match. No Map means the source code has no counterpart in the target system at all. Combination means more than one target code is required to express the full meaning of the source code. A mapping with none of these flags is considered an exact equivalent.
Are the GEMs still updated?
No. CMS published the final GEMs update with the FY 2018 release and the mappings are now a frozen reference. They remain the standard tool for converting legacy ICD-9 data, but ICD-10 codes added after the final release have no GEMs entry, so recent codes may return no mapping in the backward direction.

More Lookup Tools

ICD-10-CM LookupCurrent diagnosis codes ICD-9 LookupLegacy diagnosis codes ICD-10-PCS LookupInpatient procedure codes DRG by DiagnosisMS-DRG from a CM code Browse ICD-10-CMAll codes by chapter

Source data: the official General Equivalence Mappings published by the Centers for Medicare & Medicaid Services and the National Center for Health Statistics, loaded as published, without editorial changes. CMS issued the final GEMs update with the FY 2018 release; the mappings are a frozen reference.