What is the difference between a standard Code 128 and a GS1-128 barcode?

While both use the Code 128 bar-space symbology, a true GS1-128 barcode begins with a special non-printable FNC1 function codeword immediately after the start character and enforces strict GS1 Application Identifier rules. Switch the Symbology selector to GS1-128 mode to encode compliant logistics labels.

How does automatic Code Set C compression make my barcode narrower?

Whenever your data contains four or more consecutive digits (such as an 18-digit SSCC or numeric SKU), the encoder automatically switches to Code Set C, encoding two digits per symbol character and reducing the overall barcode width by up to 40%.

horizontal physical ruler · mm

3 mm layout guide

101.6 mm

813 × 1219 dots / 8 dpmm

Print checks

Encoding & geometry passed

1 encoded symbols / 0 warnings / 0 engine errors

Check Digit Status

PASS (Code sets optimized; Mod-103 encoded)

Validation is recalculated from the current source. Invalid identifiers do not produce a symbol.

Quiet Zone Clearance

PASS (Min margin: 29.8 mm)

Required L/R/T/B: 3.75 / 3.75 / 3.00 / 3.00 mm. Includes 3 mm layout clearance and symbology module minima.

left	29.88 mm / guide 26.88
right	29.75 mm / guide 26.75
top	51.75 mm / guide 48.75
bottom	82.63 mm / guide 79.63

Effective DPI	203.2
Dot pitch	0.1250 mm
Raster width	813 dots
Raster height	1219 dots

Technical specifications

Code 128 / GS1-128 specifications
Parameter	Specification
Code Sets	Automatic Code Set A, B, and C switching (pairs of digits compressed via Code Set C)
Integrity Check	Mandatory internal weighted Modulo 103 symbol check character
GS1-128 & SSCC Mode	Leading FNC1 codeword, AI (00) 18-digit SSCC Mod-10 calculator, and ASCII 29 separators
Batch Capabilities	CSV identifier/quantity/caption mapping and sequential carton numbering

Parameter

Specification

Code Sets

Automatic Code Set A, B, and C switching (pairs of digits compressed via Code Set C)

Integrity Check

Mandatory internal weighted Modulo 103 symbol check character

GS1-128 & SSCC Mode

Leading FNC1 codeword, AI (00) 18-digit SSCC Mod-10 calculator, and ASCII 29 separators

Batch Capabilities

CSV identifier/quantity/caption mapping and sequential carton numbering

Printer settings use 8 / 12 / 24 dots per millimeter. Nominal 203 / 300 / 600 DPI names correspond to effective 203.2 / 304.8 / 609.6 DPI device grids. Screen dimensions use the CSS reference of 96 px/in.

Operating procedure

Choose ordinary Code 128 or the GS1-128 / SSCC logistics mode.

Enter the payload or GS1 Application Identifiers and align the symbol to the printer dot grid.

Resolve preflight diagnostics before exporting files or a quantity-expanded batch print sheet.

Preflight validates supported identifiers and geometry; it does not certify scanner grades. Fix every red error before exporting.

Frequently asked questions

Tools

Pages

Navigation

Code 128 Barcode Generator (Auto Code Set A/B/C)

Print checks

Check Digit Status

Quiet Zone Clearance

X-Dimension

Printhead Dot Alignment

Element Bounds

Technical Specifications & Implementation Guide

Technical specifications

Operating procedure

Frequently asked questions