GS1 Format and Application Identifiers Guide

What is GS1? GS1 is a global standards organization that develops and maintains supply chain standards, including barcodes, for tracking products, shipments, and assets worldwide.

📋 Introduction to GS1 Application Identifiers

Application Identifiers (AIs) are standardized prefixes that define the meaning and format of data elements in GS1 barcodes. They enable structured encoding of multiple data fields within a single barcode.

Key Characteristics

Prefix Structure: 2-4 digit numerical prefixes that identify data type
Data Format: Each AI defines specific format rules for the following data
Separator Function: FNC1 characters separate variable-length fields
Global Standard: Recognized worldwide for supply chain tracking

GS1 Data Structure

Basic Format:

[AI][Data][FNC1][AI][Data][FNC1]...

Components:

Application Identifier (AI): 2-4 digit prefix
Data Field: Actual data in specified format
FNC1: Field separator for variable-length fields (Note: the field separator is added automatically by the web generator)

Example Breakdown:

Raw Data:
011234567890123415190521103210Ab1234

01 GTIN: 12345678901234
15 Best Before: 190521
10 Batch: 3210Ab1234

Generate GS1 compliant barcodes

Application Identifiers (AIs) are entered in the text field using brackets : []. For instance the Best Before Date AI will be entered as [15], followed by the date

Data to be encoded:
[01]12345678901234[15]190521[10]3210Ab1234

GTIN AI: [01] GTIN value: 12345678901234
Best before AI [15] Best Before date: 190521
Batch AI [10] Batch value: 3210Ab1234

Common Application Identifiers

AI	Description	Format	Length	Example
00	Serial Shipping Container Code (SSCC)	Numeric	18 digits (fixed)	`001234567890123456`
01	Global Trade Item Number (GTIN)	Numeric	14 digits (fixed)	`12345678901231`
10	Batch or Lot Number	Alphanumeric	1-20 chars (variable)	`ABC123`
11	Production Date	YYMMDD	6 digits (fixed)	`241010`
15	Best Before Date	YYMMDD	6 digits (fixed)	`251210`
17	Expiration Date	YYMMDD	6 digits (fixed)	`251215`
21	Serial Number	Alphanumeric	1-20 chars (variable)	`SN123456`
240	Additional Product Identification	Alphanumeric	1-30 chars (variable)	`PRODUCT-VARIANT-A`
310n	Net Weight (kg)	Numeric (n=decimal places)	6 digits (fixed)	`3101001250` (12.50 kg)
37	Number of Units Contained	Numeric	1-8 digits (variable)	`24`

Measurement Application Identifiers (3xxx Series)

The 3xxx series AIs are used for various measurements. The last digit (n) indicates the number of decimal places.

Weight Measurements:

310n: Net weight (kg)
311n: Length/width/height (meters)
312n: Width (meters)
313n: Depth/thickness (meters)
314n: Area (square meters)
315n: Net volume (liters)

Imperial Measurements:

320n: Net weight (pounds)
321n: Length/width/height (inches)
322n: Width (inches)
323n: Depth/thickness (inches)
324n: Area (square inches)
325n: Net volume (quarts)

Decimal Place Examples:
3101001250 = 12.50 kg (1 decimal place)
3102001250 = 1.250 kg (2 decimal places)
3103001250 = 0.1250 kg (3 decimal places)

Practical Examples

Example 1: Food Product

Encoded Data:
011234567890123415251210103210ABC

01 GTIN: 12345678901231
15 Best Before: December 10, 2025
10 Batch: 3210ABC

Example 2: Shipping Container

Encoded Data:
0098765432109876543111241010

00 SSCC: 98765432109876543
11 Production Date: October 10, 2024

Example 3: Complex Product with Measurements

Encoded Data:
01123456789012311525121021SN78910031010012503720024

01 GTIN: 12345678901231
15 Best Before: December 10, 2025
21 Serial Number: SN78910

3101 Net Weight: 12.50 kg
37 Units Contained: 24 pieces

Technical Implementation Guidelines

Encoding Rules:

Do not encode bracket symbols [] in actual barcode
Use FNC1 (Function Code 1) as field separator
FNC1 represented as \F in some systems
Terminate variable-length fields with FNC1
Omit FNC1 after the last data field
Check digit validation for GTIN and SSCC

Validation Tips:

Verify AI format against official GS1 specifications
Validate data length constraints
Check date format (YYMMDD) validity
Ensure alphanumeric fields use allowed characters
Implement check digit algorithms for numeric IDs
Test barcode readability across different scanners

Compatible Barcode Types

Linear Barcodes:

GS1-128: Most common for GS1 data
GS1 DataBar: Compact linear format
ITF-14: For GTIN-14 only

2D Barcodes:

GS1 Data Matrix: High density 2D
GS1 QR Code: Quick Response format
GS1 Composite: Combined linear + 2D

Use Cases:

Retail: GTIN + price/weight
Healthcare: Lot numbers + expiry
Logistics: SSCC + tracking info

Quick Reference

Fixed Length AIs:

`00`	SSCC (18)
`01`	GTIN (14)
`11`	Production Date (6)
`15`	Best Before (6)
`17`	Expiry Date (6)
`310n-315n`	Measurements (6)

Variable Length AIs:

`10`	Batch/Lot (1-20)
`21`	Serial Number (1-20)
`240`	Additional ID (1-30)
`37`	Count (1-8)
`90-99`	Company Internal (1-30)

Additional Resources

Official GS1 Resources:

Tools and Generators:

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