Barcode Generation and Barcode Systems

Choosing a Symbology Is a Technical Decision

It is not a design preference. A job printed with the wrong symbology has to be produced again because it will not scan. The choice depends on what data you carry, where the code will be read and how much space you have.

The Main Options

• Code 128 — letters and digits, flexible length, high density. The default for internal tracking.
• Code 39 — older and wider. Only for compatibility with legacy readers.
• EAN-13 — retail. Allocated through GS1 membership; cannot be self-assigned.
• DataMatrix — very small footprint, tolerates partial damage. Standard on electronics and medical devices.
• GS1-128 — batch, expiry and quantity in one symbol with standard identifiers.
• ITF-14 — outer cases and cartons; tolerant of coarse printing surfaces.

What Determines Readability

Three things: bar width, the quiet zone on either side, and contrast. Requests to shrink a label usually take from the first two. Dark bars on a light background is the expectation — red bars are read as white by many scanners.

Orientation

The code orientation must match how it will be scanned. A vertically placed "ladder" barcode will not read on a fixed horizontal scanner.

Verification

Samples from the start, middle and end of a run are scanned with a real reader. On-screen enlargement is misleading; testing must happen at actual print size, on the actual material.

Free Tool

For a single barcode, our free barcode generator covers 36 formats and exports to PNG, JPEG, SVG, PDF or AI. For thousands of different barcodes see variable barcode labels.