What is Code 39?
Code 39 (also called Code 3 of 9) is a simple alphanumeric barcode that can encode uppercase letters, digits and a few symbols. It is common in industrial, government, military and asset-tracking applications because it is easy to read and widely supported.
Common Uses for Code 39
- Asset and equipment tracking tags
- Government and military ID labels
- Library and document management
- Automotive and manufacturing parts
Code 39 vs Code 128
Both Code 39 and Code 128 are alphanumeric barcodes. Code 39 is simpler and widely supported by older scanners, but it's low-density (roughly 40% more space for the same data) and can't encode lowercase letters. Code 128 is denser, encodes the full ASCII set, and is a better choice for long strings or new implementations. Code 39 is still preferred in some government and automotive standards that mandate it.
Code 39 Character Set
Standard Code 39 encodes 43 characters: uppercase A-Z, digits 0-9, and the symbols minus (-), period (.), space, dollar ($), slash (/), plus (+) and percent (%). Extended Code 39 (Code 39 Full ASCII) can encode the entire ASCII set by combining pairs, but at the cost of density. If your data needs lowercase letters, use Code 128 instead.