About this tool
Barcode structures are standard machine-readable visual patterns utilized to accelerate shipping logistics, inventory audits, and retail checkouts globally. This generator offers complete offline Code 39 barcode compilation.
Polynomial Check-Digit Calculations
Robust industrial formats (such as UPC and EAN standard configurations) rely on error-checking polynomial check digits to prevent scanner reader misinterpretations. This check digit calculation adds weighting scales to numeric positions recursively:
Where:
- di represents the raw digit at position i in the number coordinate string.
This local Canvas rendering engine prints clean, high-contrast, scalable black-and-white lines that smartphone cameras and retail scanners can decode from any angle.
Frequently asked questions
Everything you need to know about Barcode Generator.
Which barcode formats does the generator support?
The tool supports CODE128 (alphanumeric, variable length — most versatile), EAN-13 (European retail), EAN-8 (small packaging), UPC-A (North American retail), UPC-E (compact retail), CODE39 (industrial/logistics), and ITF-14 (shipping containers).
What is the difference between UPC-A and EAN-13?
UPC-A is a 12-digit barcode used predominantly in the United States and Canada. EAN-13 is a 13-digit superset (UPC-A is EAN-13 with a leading 0) used internationally. All modern barcode scanners can read both formats.
Can any barcode scanner read the barcodes generated here?
Yes, provided the barcode is printed at sufficient resolution and contrast. The tool generates standard-compliant barcodes. Phone cameras with a barcode scanner app, retail POS systems, and warehouse scanners all read them correctly.
What resolution and size should I use for printing barcodes?
For retail shelf labels, export at 300 DPI at a minimum of 3.7cm wide (EAN-13/UPC-A spec). For industrial use, 203–300 DPI is standard. Always print a test scan on your actual scanner before mass printing.
Is there a character limit for CODE128 barcodes?
CODE128 has no strict maximum, but barcode length grows linearly with character count. Practical limits for reliable scanning are 20–25 characters for small labels and up to 48 characters for larger labels with generous quiet zones.