The Current Procedural Terminology (CPT) code set is maintained by the American Medical Association through the CPT Editorial Panel. The CPT code set accurately describes medical, surgical, and diagnostic services and is designed to communicate uniform information about medical services and procedures among physicians, coders, patients, accreditation organizations, and payers for administrative, financial, and analytical purposes. The current version is the CPT 2018.
There are three types of CPT codes:
CPT is currently identified by the Centers for Medicare and Medicaid Services (CMS)  as Level 1 of the Health Care Procedure Coding System.
CPT is a registered trademark of the American Medical Association. The AMA holds copyright which prevents free use and distribution of codes.
Although the CPT system is mandated by the Centers for Medicare and Medicaid Services (CMS) and HIPAA, and the data for it appear in the Federal Register, the American Medical Association (AMA) maintains that their copyright of the CPT allows them to charge a license fee to anyone who wishes to associate Relative Value Unit (RVU) values with CPT codes. The AMA receives approximately $70 million annually from these fees, making them reluctant to allow the free distribution of tools and data that might help physicians calculate, record, or submit their fees accurately and fairly.
The AMA offers a personal, non-commercial search of the Current Procedural Terminology, Fourth Edition ("CPT") manual on its website:
Unfortunately, this tool limits not only the number of codes anyone can look up, but it doesn't provide helpful information (such as the component values of each code or the ability to use an individual fee multiplier) or provide the results in a manner that can be easily adopted to a spreadsheet for analysis, etc. For providers or patients to fairly assess medical charges, they must pay the AMA a license fee.