Developer Barcodes

Barcode generator

Value

Twelve digits and the thirteenth is calculated for you, or paste all thirteen to have it checked. This is the retail barcode used everywhere outside North America.

Encoded 9780201379624 · 95 modules · check digit 4

Bar width 2 Height 70 Print the number under the bars

Live · check digit calculated and validated

A linear barcode encodes digits or characters as a pattern of bars and spaces of varying width. Retail codes — EAN-13, UPC-A, EAN-8 and ITF-14 — end in a check digit calculated from the ones before it, which is how a scanner knows it read the number correctly. Code 128 and Code 39 accept text as well as digits.

How to make a barcode

1 Choose the symbology. The hint underneath says what it accepts.

2 Type the value. The check digit is calculated for you, or validated if you supply it.

3 Set the bar width and height for your label, then download SVG for print or PNG for a screen.

A retail barcode number is not something you can invent. GTINs are issued by GS1, and the first digits identify the company that owns them — printing a number you do not hold will scan, and will ring up as somebody else’s product. This generator will happily encode any valid number; whether you are entitled to use it is a separate question.

Questions

How is the check digit worked out? −

For EAN and UPC, digits are weighted alternately by one and three, summed, and the check digit is whatever brings the total to a multiple of ten. Enter the number without it and you will see the digit that gets added.

Why is my Code 128 shorter than expected? +

Which one should I use? +

How wide should the bars be? +

Can I make a sheet of them? +

Sources

GS1 — general specifications ISO/IEC 15417 — Code 128 bar code symbology specification

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