Code 39 Barcode Generator
Generate Code 39 barcodes
Frequently Asked Questions
What characters can Code 39 encode?
Code 39 encodes: digits 0-9, uppercase letters A-Z, and symbols - . $ / + % SPACE. Total of 43 characters. It cannot encode lowercase letters. Extended Code 39 uses character pairs to represent all 128 ASCII characters but doubles the barcode length.
Why is Code 39 called "Code 3 of 9"?
Each character is represented by 9 elements (5 bars and 4 spaces), of which 3 are wide. The ratio of wide to narrow elements is typically 2.5:1 or 3:1. Start and stop characters are asterisks (*). The generator handles formatting automatically.
Where is Code 39 commonly used?
Code 39 is used in automotive (AIAG standard), defense (MIL-STD-1189), healthcare (HIBC), and government (LOGMARS). It is self-checking (no mandatory checksum), making it reliable for industrial environments with dust and vibration.
What is the minimum size for a Code 39 barcode?
Minimum narrow bar width: 0.19 mm (7.5 mil). Recommended: 0.25-0.50 mm. Height: at least 6.35 mm or 15% of symbol length. Quiet zone: 10× narrow bar width on each side. Wider bars improve scan reliability at distance.
How do I add a check digit to Code 39?
Code 39 check digit: assign values 0-42 to each character, sum all values, divide by 43, the remainder maps to the check character. Example: "CODE" = 12+24+13+14 = 63, 63 mod 43 = 20 = "K". The generator can add check digits automatically.