Free Barcode Generator
Generate standard Code 39 barcodes. Adjust line scaling, dimensions, and styling. Completely offline client-side code execution.
Barcode Settings
Code 39What is Code 39 Barcode Format?
Industrial Standard Symbol
Code 39 (also known as Code 3 of 9) is a variable-length, discrete barcode symbology widely used in inventory control, automotive logistics, and governmental administrative forms. It can encode 43 unique characters including capital letters, numbers, and key symbols. The name stems from its structure where 3 out of every 9 lines representing a character are wide.
Self-Checking Symbology
Unlike barcode systems like EAN/UPC which require strict mathematical parity checks to scan, Code 39 is self-checking. Any single character reading error will result in an invalid sequence rather than misreading one character for another, making it highly robust for standard physical laser scanner registers.
Frequently Asked Questions
Why does the barcode container have asterisk symbols?
In Code 39, the asterisk character `*` is reserved exclusively as the start and stop delimiter. Scanners look for the start `*` to determine scan direction and the end `*` to stop recording.
Can I use lowercase letters?
Standard Code 39 does not support lowercase letters. Our generator automatically converts lowercase characters to uppercase to preserve scan compliance.
How to Use Barcode Generator
Enter Barcode Payload
Type your alphanumeric product code, SKU, or tracking ID (supported: A-Z, 0-9, space, -, ., $, /, +, %).
Adjust Bar Dimensions
Use sliders to customize bar thickness (1px-4px) and total barcode height (50px-200px).
Toggle Text Labels
Choose whether to display human-readable text labels below the barcode symbol.
Download Vector or Image
Export as resolution-independent vector SVG or crisp PNG image.
Key Features & Capabilities
- Standard Code 39 industrial symbology
- Custom bar thickness and height controls
- Human-readable text label toggle
- Vector SVG and PNG download formats
- 100% private client-side processing
100% Client-Side Privacy: All operations occur locally in your web browser memory using JavaScript and WebAssembly. Your files, text payloads, and images are never uploaded to external servers or stored in cloud databases.
Frequently Asked Questions
View All Platform FAQsWhat characters are supported in Code 39 barcodes?
Code 39 supports capital letters (A-Z), digits (0-9), space, and symbols (- . $ / + %). Lowercase letters are automatically converted to uppercase.
Why are asterisk (*) symbols included in the text label?
In Code 39 symbology, asterisks serve as required start and stop delimiters so physical laser scanners can detect scan bounds and direction.
Experiencing an issue with Free Barcode Generator?
Notice a bug, calculation error, or unexpected result? Let us know.