Code 39 Barcode Generator

Code 39 is self-checking, meaning it doesn't strictly require a checksum digit for low-density applications. However, an optional Modulo 43 check digit can be added for high-security data requirements.

Standard Code 39 supports uppercase letters (A-Z), numbers (0-9), and seven special characters: space, minus (-), period (.), dollar sign ($), slash (/), plus (+), and percent (%).

The name comes from its structure: each character is represented by 9 bars (five black, four white), and exactly 3 of these bars are wide, hence "3 of 9".