ICD Code Reference

Convert between ICD-9 and ICD-10 codes.

Quickly convert diagnostic codes between ICD-9 and ICD-10 formats using our integrated tool.

Understanding ICD codes

ICD-9 codes

The International Classification of Diseases, 9th Revision (ICD-9) was used in the United States until October 2015. ICD-9 codes are typically 3–5 digits long. Example: 250.00 (Diabetes mellitus).

ICD-10 codes

The International Classification of Diseases, 10th Revision (ICD-10) has been used since October 2015. ICD-10 codes provide more specificity — alphanumeric codes 3–7 characters long. Example: E11.9 (Type 2 diabetes mellitus).

Why convert?

  • Reviewing historical patient records
  • Comparing legacy data with current diagnoses
  • Understanding equivalent diagnostic classifications
  • Ensuring continuity of care documentation

Conversion tips

  • Not all codes have direct one-to-one equivalents.
  • ICD-10 provides more specific diagnoses.
  • Some ICD-9 codes map to multiple ICD-10 codes.
  • Always verify the clinical accuracy of conversions.

Additional resources