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Code 128 barcodes for UPS shipping labels

UPS shipping labels use Code 128 barcodes (often wrapped as GS1-128 with FNC1 separator and Application Identifiers) to encode the tracking number and routing data. The label also includes a MaxiCode 2D barcode for UPS's automated sorting — both must be present for the label to clear an automated UPS facility.

Generate

If you're printing your own labels through UPS Worldship, UPS API, or a multi-carrier platform (ShipStation, Shippo, Easypost), Code 128 generation is handled automatically. This page is for cases where you need to render a standalone Code 128 with specific data — e.g., internal tracking, custom labels, or test prints.

Step by step

1. 1

   Generate the tracking-number Code 128

   Use the generator above. UPS tracking format is '1Z' + 6-char shipper number + 2-char service code + 8-char package count.

2. 2

   Optional: GS1-128 with AI prefixes

   For supply-chain integration (Application Identifiers prefixed to each segment: 00=SSCC, 01=GTIN, 17=Best By, 21=Serial). Use a GS1-aware generator for proper FNC1 + AI encoding.

3. 3

   Print at minimum 12.7mm height

   UPS label spec: 4×6 inch labels, Code 128 at minimum 0.5 inch (12.7mm) bar height. Higher contrast = better automated sorting.

4. 4

   Pair with MaxiCode

   UPS automated facilities scan MaxiCode first. Without it, the label downgrades to manual sort — slower and more expensive.

Gotchas

• UPS rejects Code 128 labels printed too small (under 0.5 inch tall). Auto-sort throws them out.
• Custom Code 128 not tied to a real UPS tracking number can't ship through UPS — they're only valid for your own internal tracking.
• Direct thermal labels fade over time. For long-haul international shipments, use thermal transfer for legibility.

FAQ

Related

• Code 128 generator — standalone generator without UPS steps.
• All UPS barcode guides
• All platforms