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GS1-128 Barcode Decoder

Parse GS1-128 application identifiers out of a barcode data string.

Identification & SerialsFree
INPUT
OUTPUT

The result appears here as you type.

Decoding runs in your browser. What you paste is not sent to a server.

A GS1-128 decoder splits a barcode data string into its Application Identifiers — two- to four-digit codes such as (01) for GTIN, (10) for batch and (17) for expiry — and the value that follows each one.

Example

Input
(01)09501101530003(17)261231(10)AB-123(21)12345
Output
(01) GTIN: 09501101530003  [check digit valid]
(17) Expiration date: 2026-12-31
(10) Batch or lot number: AB-123
(21) Serial number: 12345
Elements: 4
Validation: ✓ all elements valid

What is the GS1-128 Barcode Decoder?

GS1-128 carries structured data rather than a single number. Each field opens with an Application Identifier that defines what the field means and how long it is: (01) is a 14-digit GTIN, (17) a 6-digit expiry date as YYMMDD, (10) a variable-length batch or lot, (21) a variable-length serial number, (00) an 18-digit SSCC identifying a logistics unit.

The fixed-versus-variable distinction is the whole parsing problem. Fixed-length AIs can simply be read off in sequence, but a variable-length field runs until a GS separator character (ASCII 29) or the end of the string. Miss a separator and every field after it is misread — the usual cause of a pallet label that scans but produces nonsense.

This is the encoding behind pharmaceutical serialisation, food traceability and logistics labels, where a single scan must yield product, batch, expiry and serial at once.

How to use the GS1-128 Barcode Decoder

  1. Paste the raw scanned data string, keeping any GS separator characters intact.
  2. Read each identified Application Identifier and its decoded value.
  3. Check that variable-length fields terminated where you expected them to.

When to use it

  • Debugging a warehouse scanner that misreads pallet labels.
  • Verifying pharmaceutical serialisation data on a printed carton.
  • Extracting batch and expiry data for a traceability system.

GS1-128 Barcode Decoder at a glance

(01)GTIN — 14 digits, fixed length
(17)Expiry date, YYMMDD, fixed length
(10) / (21)Batch / serial — variable length, GS-terminated
SeparatorGS character, ASCII 29, ends variable fields

Frequently asked questions

What are the brackets in a GS1-128 code?

A human-readable convention only. The parentheses around an AI are printed under the barcode for people to read; they are not part of the encoded data.

Why does my scan produce garbled fields?

A missing GS separator after a variable-length field. Without it the parser keeps consuming digits into the next AI, and everything downstream is wrong.

What is an SSCC?

Serial Shipping Container Code, AI (00) — an 18-digit identifier for a logistics unit such as a pallet, unique enough to track that specific unit through a supply chain.

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