The Code 39 (3 of 9) Barcode Guide
Reliable alphanumeric simplicity. Master the classic discrete symbology used in military, automotive, and industrial asset tracking systems.
What is Code 39?
Code 39 (also known as 3 of 9) is one of the oldest and most widely used alphanumeric barcodes. Its name comes from the fact that each character is represented by nine elements (bars or spaces), exactly three of which are wide.
Start and Stop Asterisks
Every Code 39 barcode must begin and end with an asterisk (*) character. These characters serve as start and stop symbols, instructing the scanner when to begin interpreting data. While they are mandatory in the encoded pattern, they are usually omitted from the human-readable text.
Discrete Character Set
Code 39 is a "discrete" symbology, meaning each character is separated by a small gap (intercharacter gap) and can be interpreted independently. It natively supports 43 characters:
- Uppercase Letters: A through Z.
- Digits: 0 through 9.
- Symbols: Space, Dash (-), Period (.), Dollar ($), Slash (/), Plus (+), Percent (%).