ISO/IEC 15420:2025

Information technology - Automatic identification and data capture techniques - EAN/UPC bar code symbology specification

This document specifies the requirements for the bar code symbology known as EAN/UPC. This document specifies EAN/UPC symbology characteristics, data character encodation, dimensions, tolerances, decoding algorithms and parameters to be defined by applications. It specifies the symbology identifier prefix strings for EAN/UPC symbols. Data content and the rules governing the use of this symbology are outside the scope of this document; they are defined in GS1 General Specifications.

Technologies de l'information — Techniques automatiques d'identification et de capture des données — Spécification de symbologie de code à barres EAN/UPC

General Information

• Status: Published
• Publication Date: 18-Nov-2025
• ICS: 01.080.50 - Graphical symbols for use on information technology and telecommunications technical drawings and in relevant technical product documentation
• ICS: 35.040.50 - Automatic identification and data capture techniques
• Technical Committee: ISO/IEC JTC 1/SC 31 - Automatic identification and data capture techniques
• Drafting Committee: ISO/IEC JTC 1/SC 31 - Automatic identification and data capture techniques
• Current Stage: 6060 - International Standard published
• Start Date: 19-Nov-2025
• Due Date: 30-Mar-2025
• Completion Date: 19-Nov-2025

Relations

• Revises: ISO/IEC 15420:2009 - Information technology - Automatic identification and data capture techniques - EAN/UPC bar code symbology specification
• Effective Date: 06-Jun-2022

Overview

ISO/IEC 15420:2025 - Information technology - Automatic identification and data capture techniques - EAN/UPC bar code symbology specification - is the international standard that defines the EAN/UPC bar code symbology used worldwide for retail and logistics identification. The third edition (2025) specifies the symbology characteristics, character encodation, symbol formats, dimensions and tolerances, decoding algorithms, verification and quality requirements, and symbology identifier prefixes. Data content rules (for example GTIN assignment) are intentionally outside its scope and are maintained in the GS1 General Specifications.

Key technical topics and requirements

• Encodable character set: numeric (digits 0–9) per ISO/IEC 646.
• Symbology types: EAN-13, UPC-A, UPC-E (each may include add-on symbols) and EAN-8.
• Character structure: each data character is encoded as a 7-module pattern (4 elements: 2 bars and 2 spaces) from number sets A, B and C with defined parity behavior.
• Symbol mechanics: continuous symbology, omni-directional decoding capability, and a mandatory single symbol check digit.
• Dimensions & tolerances: measurement basis and parameters such as narrow element (X) width, bar height, quiet zone, element widths, symbol width/size and dimensional tolerances are specified.
• Decoding: a reference decode algorithm and application-defined parameters are provided to ensure interoperability.
• Quality & verification: test methodology, decodability metrics and additional quality criteria; verification lighting updated in this edition from 670 nm to 660 nm to align with GS1.
• Auxiliary and guard patterns: definitions for normal/centre/special guard patterns and add-on patterns.
• Normative annexes and informative guidance: include additional features, symbology identifier strings, an overview of the GS1 system, dimensioned drawings and printing/reading guidelines.

Practical applications and who uses this standard

• Manufacturers of barcode printers, scanners and verifier equipment ensuring correct encoding and reliable decoding.
• Software developers implementing barcode generation, decoding algorithms, and label layout engines.
• Retailers, distributors and logistics operators implementing AIDC for point-of-sale (POS), inventory tracking and supply-chain automation.
• Standards bodies and testing laboratories performing barcode conformance and print quality verification.
• Integrators and consultants working with GTIN and GS1-based identification systems.

Related standards

• GS1 General Specifications (data content and assignment rules)
• ISO/IEC 15416 - Bar code print quality test specification - Linear symbols
• ISO/IEC 19762 - AIDC vocabulary

ISO/IEC 15420:2025 is essential for interoperable EAN/UPC implementation across the retail and logistics ecosystem, providing the technical baseline for consistent barcode production, verification and decoding. Keywords: ISO/IEC 15420:2025, EAN/UPC, barcode symbology, AIDC, GTIN, GS1, decoding algorithm, barcode verification, dimensions and tolerances.

Standards Content (Sample)

International
Standard
ISO/IEC 15420
Third edition
Information technology —
2025-11
Automatic identification and data
capture techniques — EAN/UPC bar
code symbology specification
Technologies de l'information — Techniques automatiques
d'identification et de capture des données — Spécification de
symbologie de code à barres EAN/UPC
Reference number
© ISO/IEC 2025
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
© ISO/IEC 2025 – All rights reserved
ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Requirements . 2
4.1 Symbology characteristics.2
4.2 Symbol structure .2
4.2.1 Symbol types .2
4.2.2 Symbol encodation .2
4.2.3 Symbol formats . .4
4.3 Dimensions and tolerances . . 12
4.3.1 Measurement basis . 12
4.3.2 Width of narrow element (X) . 12
4.3.3 Bar height . 12
4.3.4 Quiet zone . 12
4.3.5 Positioning of the add-on symbol . 13
4.3.6 Element widths . 13
4.3.7 Symbol width . 13
4.3.8 Symbol size .14
4.3.9 Dimensional tolerances .14
4.4 Reference decode algorithm .14
4.5 Symbol quality .18
4.5.1 Test methodology .18
4.5.2 Decodability . .19
4.5.3 Additional criteria .19
4.6 Application-defined parameters . 20
4.7 Human-readable interpretation . . 20
4.8 Transmitted data . 20
4.9 Implementation guidelines . 20
Annex A (normative) Additional features .21
Annex B (normative) Symbology identifier .23
Annex C (informative) Overview of the GS1 system.24
Annex D (informative) Illustration of number sets A, B and C and auxiliary patterns .25
Annex E (informative) Dimensioned drawings of the nominal size symbols .28
Annex F (informative) Traditional dimensional tolerances .33
Annex G (informative) Guidelines for reading and printing .35
Bibliography .37

© ISO/IEC 2025 – All rights reserved
iii
Foreword
ISO (the International Organization for Standardization) and IEC (the International Electrotechnical
Commission) form the specialized system for worldwide standardization. National bodies that are
members of ISO or IEC participate in the development of International Standards through technical
committees established by the respective organization to deal with particular fields of technical activity.
ISO and IEC technical committees collaborate in fields of mutual interest. Other international organizations,
governmental and non-governmental, in liaison with ISO and IEC, also take part in the work.
The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types
of document should be noted. This document was drafted in accordance with the editorial rules of the ISO/
IEC Directives, Part 2 (see www.iso.org/directives or www.iec.ch/members_experts/refdocs).
ISO and IEC draw attention to the possibility that the implementation of this document may involve the
use of (a) patent(s). ISO and IEC take no position concerning the evidence, validity or applicability of any
claimed patent rights in respect thereof. As of the date of publication of this document, ISO and IEC had not
received notice of (a) patent(s) which may be required to implement this document. However, implementers
are cautioned that this may not represent the latest information, which may be obtained from the patent
database available at www.iso.org/patents and https://patents.iec.ch. ISO and IEC shall not be held
responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT) see www.iso.org/iso/foreword.html.
In the IEC, see www.iec.ch/understanding-standards.
This document was prepared by Joint Technical Committee ISO/IEC JTC 1, Information technology,
Subcommittee SC 31, Automatic identification and data capture techniques.
This third edition cancels and replaces the second edition (ISO/IEC 15420:2009), which has been technically
revised.
The main changes are as follows:
— terminology and dimensions have been updated to align with latest GS1 General Specifications;
— clarification on what is defined in this document compared to an application standard has been added;
— example barcodes have been revised to use GS1 company prefixes reserved for examples;
— verification lighting has been changed from 670 nm to 660 nm to align with GS1 General Specifications.
Any feedback or questions on this document should be directed to the user’s national standards
body. A complete listing of these bodies can be found at www.iso.org/members.html and
www.iec.ch/national-committees.

© ISO/IEC 2025 – All rights reserved
iv
Introduction
The technology of bar coding is based on the recognition of patterns encoded in bars and spaces of defined
dimensions. There are numerous methods of encoding information in bar code form, known as symbologies.
EAN/UPC is one such symbology. The rules defining the translation of characters into bar and space patterns,
and other essential features of each symbology, are known as the symbology specification.
This document is intended to be used alongside the GS1 General Specifications. The administration of
the numbering system by GS1 ensures that identification codes assigned to particular items are unique
1)
worldwide and are defined in a consistent way. The major benefit for the users of the GS1 system is the
availability of uniquely defined identification codes for use in their trading transactions. Annex C gives an
overview of the GS1 system.
NOTE GS1 is the worldwide association encompassing the organizations formerly known as EAN International
and Uniform Code Council (UCC).
Manufacturers of bar code equipment and users of bar code technology require publicly available standard
symbology specifications to which they can refer when developing equipment and software.
1) The GS1 system are specifications, standards, and guidelines administered by GS1.

© ISO/IEC 2025 – All rights reserved
v
International Standard ISO/IEC 15420:2025(en)
Information technology — Automatic identification and
data capture techniques — EAN/UPC bar code symbology
specification
1 Scope
This document specifies the requirements for the bar code symbology known as EAN/UPC. This document
specifies EAN/UPC symbology characteristics, data character encodation, dimensions, tolerances, decoding
algorithms and parameters to be defined by applications. It specifies the symbology identifier prefix strings
for EAN/UPC symbols.
Data content and the rules governing the use of this symbology are outside the scope of this document; they
are defined in GS1 General Specifications.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes
requirements of this document. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
ISO/IEC 646, Information technology — ISO 7-bit coded character set for information interchange
ISO/IEC 15416, Automatic identification and data capture techniques — Bar code print quality test specification
— Linear symbols
ISO/IEC 19762, Information technology — Automatic identification and data capture (AIDC) techniques —
Vocabulary
2)
GS1 General Specifications (GS1, Brussels, Belgium)
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO/IEC 19762 and the following apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
auxiliary pattern
pattern of bars and spaces representing non-data components of the symbol
EXAMPLE Guard patterns and inter-character delineators.
3.2
GTIN
Global Trade Item Number
GS1 identification key that is used for the unique identification of trade items worldwide and which may be
8, 12, 13 or 14 digits in length
2) Available at www .gs1 .org.

© ISO/IEC 2025 – All rights reserved
3.3
number set
series of ten bar and space patterns of either even or odd parity encoding the digits 0 to 9
4 Requirements
4.1 Symbology characteristics
The characteristics of EAN/UPC are:
a) encodable character set: numeric (0 to 9) i.e. ASCII characters 48 to 57 inclusive, according to
ISO/IEC 646;
b) symbology type: continuous;
c) elements per symbol character: 4, comprising 2 bars and 2 spaces, each of 1, 2, 3 or 4 modules in width
(auxiliary patterns have differing numbers of elements);
d) character self-checking: yes;
e) data string length encodable: fixed (8, 12 or 13 characters including check digit depending on specific
symbol type);
f) omni-directionally decodable: yes;
g) symbol check digit: one, mandatory (see Clause A.1);
h) symbol character density: 7 modules per symbol character;
i) non-data overhead not including the check digit or quiet zones:
— 11 modules for EAN-13, EAN-8 and UPC-A symbols;
— 9 modules for UPC-E symbols.
4.2 Symbol structure
4.2.1 Symbol types
There are four types of the EAN/UPC symbol:
— EAN-13, UPC-A and UPC-E, all of which may be accompanied by an add-on symbol;
— EAN-8.
The four symbol types are described in 4.2.3.1 to 4.2.3.4 and the optional add-on symbols are described in
4.2.3.5.
4.2.2 Symbol encodation
4.2.2.1 Symbol characters
Symbol characters shall encode digit values in 7-module characters selected from different number sets
known as A, B and C, as in Table 1.

© ISO/IEC 2025 – All rights reserved
a
Table 1 — Number sets A, B and C
a a a
Set A element widths Set B element widths Set C element widths
Digit
value
S B S B S B S B B S B S
0 3 2 1 1 1 1 2 3 3 2 1 1
1 2 2 2 1 1 2 2 2 2 2 2 1
2 2 1 2 2 2 2 1 2 2 1 2 2
3 1 4 1 1 1 1 4 1 1 4 1 1
4 1 1 3 2 2 3 1 1 1 1 3 2
5 1 2 3 1 1 3 2 1 1 2 3 1
6 1 1 1 4 4 1 1 1 1 1 1 4
7 1 3 1 2 2 1 3 1 1 3 1 2
8 1 2 1 3 3 1 2 1 1 2 1 3
9 3 1 1 2 2 1 1 3 3 1 1 2
Key
S space (light)
B bar (dark)
a
The element widths are in modules.
Annex D illustrates Table 1 graphically. The sum of the bar modules in any symbol character determines its
parity. Symbol characters in number set A are odd parity characters. Symbol characters in number sets B
and C are even parity characters. Number set C characters are mirror images of number set B characters.
Symbol characters in number sets A and B always begin on the left with a light module and end on the right
with a dark module. Symbol characters in number set C begin on the left with a dark module and end on the
right with a light module.
A data character shall normally be represented by a symbol character. However, in certain specific instances
defined below (see 4.2.3.1, 4.2.3.4 and 4.2.3.5), the combination of number sets in a symbol may itself
represent either data or a check value. This technique is referred to as variable parity encodation.
4.2.2.2 Auxiliary pattern encodation
Auxiliary patterns shall be composed as shown in Table 2.
Table 2 — Auxiliary patterns
a
Element widths in modules
Number of
Auxiliary pattern
modules
S B S B S B
Normal guard pattern 3 1 1 1
Centre guard pattern 5 1 1 1 1 1
Special guard pattern 6 1 1 1 1 1 1
Add-on guard pattern 4 1 1 2
Add-on delineator 2 1 1
Key
S space (light)
B bar (dark)
a
The element widths are in modules.
Annex D illustrates these patterns graphically.
The normal guard pattern corresponds to the start and stop patterns in other symbologies. The special
guard pattern is used as a stop pattern in UPC-E symbols.

© ISO/IEC 2025 – All rights reserved
4.2.3 Symbol formats
4.2.3.1 EAN-13 symbols
The EAN-13 symbol shall be made up as follows, reading from left to right:
— a left quiet zone;
— a normal guard pattern;
— 6 symbol characters from number sets A and B in accordance with Table 3;
— a centre guard pattern;
— 6 symbol characters from number set C;
— a normal guard pattern;
— a right quiet zone.
The rightmost symbol character shall encode the check digit calculated in accordance with Clause A.1.
Since the EAN-13 symbol comprises only 12 symbol characters but encodes 13 digits of data (including
the check digit), the value of the additional digit, which is the character in the leftmost position in the data
string, shall be encoded by the variable parity mix of number sets A and B for the 6 symbol characters in the
left half of the symbol. The coding system for values of the leading digit is specified in Table 3. Figure 1 is an
example of an EAN-13 bar code symbol.
NOTE UPC-A bar patterns (see 4.2.3.3) are a subset of EAN-13, although the human-readable information, the
symbol layout and the quiet zone requirements (see 4.3.4) differ.
Table 3 — Left half of EAN-13 symbol
Number sets used for coding left half of EAN-13 symbol for the symbol character
Leading digit, implicitly
position
encoded
1 2 3 4 5 6
1 A A B A B B
2 A A B B A B
3 A A B B B A
4 A B A A B B
5 A B B A A B
6 A B B B A A
7 A B A B A B
8 A B A B B A
9 A B B A B A
NOTE 13-digit strings printed in EAN-13 begin with a number from 1 to 9. 13-digit strings that begin with 0 (e.g.,
GTIN-12) are printed using UPC-A or UPC-E.

© ISO/IEC 2025 – All rights reserved
Figure 1 — EAN-13 bar code symbol
4.2.3.2 EAN-8 symbols
The EAN-8 symbol shall be made up as follows, reading from left to right:
— a left quiet zone;
— a normal guard pattern;
— 4 symbol characters from number set A;
— a centre guard pattern;
— 4 symbol characters from number set C;
— a normal guard pattern;
— a right quiet zone.
The rightmost symbol character shall encode the check digit calculated in accordance with Clause A.1.
Figure 2 shows an example of an EAN-8 bar code symbol.
Figure 2 — EAN-8 bar code symbol
4.2.3.3 UPC-A symbols
The UPC-A symbol shall be made up as follows, reading from left to right:
— a left quiet zone;
© ISO/IEC 2025 – All rights reserved
— a normal guard pattern;
— 6 symbol characters from number set A;
— a centre pattern;
— 6 symbol characters from number set C;
— a normal guard pattern;
— a right quiet zone.
The rightmost symbol character shall encode the check digit calculated in accordance with Clause A.1.
Figure 3 shows an example of a UPC-A bar code symbol.
A UPC-A encodes a GTIN-12 data structure.
Figure 3 — UPC-A bar code symbol
4.2.3.4 UPC-E symbols
4.2.3.4.1 UPC-E symbol structure
The UPC-E symbol shall be made up as follows, reading from left to right:
— a left quiet zone;
— a normal guard pattern;
— 6 symbol characters from number sets A and B in accordance with Table 8;
— a special guard pattern;
— a right quiet zone.
The UPC-E symbol shall only be used to encode GTIN-12 data structures which commence with a zero and
contain a sequence of four or five zeroes in defined positions, as shown in Table 9. These zeros are removed
from the data during encoding by the process of zero suppression described in 4.2.3.4.2. Figure 4 shows an
example of a UPC-E bar code symbol.

© ISO/IEC 2025 – All rights reserved
A UPC-E symbol implicitly encodes a digit zero (0) as a prefix to the GTIN-12 data structure.
Figure 4 — UPC-E bar code symbol (encoding “0 12345 000058” by zero suppression)
4.2.3.4.2 Encoding of a UPC-E symbol
The following algorithm describes the encoding of a data string suitable for zero suppression:
a) Let D1, D2, D3.D12 denote the GTIN-12 data characters (including check digit). D1 shall always be 0. D12
shall be the symbol check digit calculated in accordance with the algorithm in Clause A.1. Let X1, X2.X6
denote the six symbol characters in the final UPC-E symbol.
b) Convert D2 through D11 into a symbol character string by removing zeroes in accordance with the rules
below. Note that Tables 4, 5, 6 and 7 show the layout of the symbol characters with the data characters:
1) If
— D11 equals 5, 6, 7, 8 or 9, and
— D7 to D10 inclusive are all 0, and
— D6 is not 0
then D7 to D10 are not encoded (see Table 4).
2) If
— D6 to D10 inclusive are all 0, and
— D5 is not 0
then D6 to D10 are not encoded and X6 = 4 (see Table 5).
3) If
— D4 is 0, 1 or 2, and
— D5 to D8 inclusive are all 0
then D5 to D8 are not encoded (see Table 6).
4) If
— D4 is 3, 4, 5, 6, 7, 8 or 9, and
— D5 to D9 inclusive are all 0

© ISO/IEC 2025 – All rights reserved
then D5 to D9 are not encoded and X6 = 3 (see Table 7).
c) Determine the number sets for the implicit encodation of D12 from Table 8.
d) Encode symbol characters X1 to X6 using number sets A and B as determined in b) 3).
Table 4 — Layout of symbol characters with their data characters for scenario 1
Symbol character X1 X2 X3 X4 X5 X6
Data character D2 D3 D4 D5 D6 D11
Table 5 — Layout of symbol characters with their data characters for scenario 2
Symbol character X1 X2 X3 X4 X5 X6
Data character D2 D3 D4 D5 D11 4
Table 6 — Layout of symbol characters with their data characters for scenario 3
Symbol character X1 X2 X3 X4 X5 X6
Data character D2 D3 D9 D10 D11 D4
Table 7 — Layout of symbol characters with their data characters for scenario 4
Symbol character X1 X2 X3 X4 X5 X6
Data character D2 D3 D4 D10 D11 3
Table 8 — Number sets for UPC-E symbol
Value of check Number sets used for coding UPC-E symbol according to symbol
digit D12 character position
1 2 3 4 5 6
0 B B B A A A
1 B B A B A A
2 B B A A B A
3 B B A A A B
4 B A B B A A
5 B A A B B A
6 B A A A B B
7 B A B A B A
8 B A B A A B
9 B A A B A B
EXAMPLE 1 Data has been encoded according to step b) 1):
Original data Zero suppressed Rule
0 1 2 3 4 5 0 0 0 0 5 8 1 2 3 4 5 5 2a
Number sets to encode check digit 8 B A B A A B
EXAMPLE 2 Data has been encoded according to step b) 2):
Original data Zero suppressed Rule
0 4 5 6 7 0 0 0 0 0 8 0 4 5 6 7 8 4 2b
Number sets to encode check digit 0 B B B A A A

© ISO/IEC 2025 – All rights reserved
EXAMPLE 3 Data has been encoded according to step b) 3):
Original data Zero suppressed Rule
0 3 4 0 0 0 0 0 5 6 7 3 3 4 5 6 7 0 2c
Number sets to encode check digit 3 B B A A A B
EXAMPLE 4 Data has been encoded according to step b) 4):
Original data Zero suppressed Rule
0 9 8 4 0 0 0 0 0 7 5 1 9 8 4 7 5 3 2d
Number sets to encode check digit 1 B B A B A A
NOTE The number sets used to implicitly encode the check digit are shown below the digits in the zero-suppressed
columns.
4.2.3.4.3 Decoding a UPC-E symbol
Derivation of the 12-digit data structure from the characters encoded in the UPC-E symbol can be performed
according to Table 9, using the digit at position P6 as the key.
Table 9 — Decoding of UPC-E symbol
a b
Encoded UPC-E digits Decoded number
Leading Check
P1 P2 P3 P4 P5 P6 D1 D2 D3 D4 D5 D6 D7 D8 D9 D10 D11 D12
c d
digit digit
(0) X1 X2 X3 X4 X5 0 (C) (0) X1 X2 0 0 0 0 0 X3 X4 X5 (C)
(0) X1 X2 X3 X4 X5 1 (C) (0) X1 X2 1 0 0 0 0 X3 X4 X5 (C)
(0) X1 X2 X3 X4 X5 2 (C) (0) X1 X2 2 0 0 0 0 X3 X4 X5 (C)
(0) X1 X2 X3 X4 X5 3 (C) (0) X1 X2 X3 0 0 0 0 0 X4 X5 (C)
(0) X1 X2 X3 X4 X5 4 (C) (0) X1 X2 X3 X4 0 0 0 0 0 X5 (C)
(0) X1 X2 X3 X4 X5 5 (C) (0) X1 X2 X3 X4 X5 0 0 0 0 5 (C)
(0) X1 X2 X3 X4 X5 6 (C) (0) X1 X2 X3 X4 X5 0 0 0 0 6 (C)
(0) X1 X2 X3 X4 X5 7 (C) (0) X1 X2 X3 X4 X5 0 0 0 0 7 (C)
(0) X1 X2 X3 X4 X5 8 (C) (0) X1 X2 X3 X4 X5 0 0 0 0 8 (C)
(0) X1 X2 X3 X4 X5 9 (C) (0) X1 X2 X3 X4 X5 0 0 0 0 9 (C)
a
The symbol characters at positions P1, P2 . P5 of the UPC-E symbol are represented by X1, X2 . X5.
b
Re-inserted zeroes are shown in underlined bold type, in shaded cells.
c
The leading zero digit for UPC-E symbols, which is not directly encoded, is indicated by “(0)”.
d
The GTIN-12 check digit implicitly encoded in UPC-E (by the mix of number sets) is indicated by “(C)”.
4.2.3.5 Add-on symbols
4.2.3.5.1 General
The add-on symbols were originally designed for use with EAN/UPC symbols on periodicals and paperback
books. Given that they provide reduced security, their use shall be limited to applications where rules in the
application specification governing data format and content provide appropriate safeguards.
4.2.3.5.2 Two-digit add-on symbol
The 2-digit add-on may be used in combination with an EAN-13, UPC-A or UPC-E symbol. The add-on is
positioned following the right quiet zone of the main symbol and consists of the following:
— add-on guard pattern;
© ISO/IEC 2025 – All rights reserved
— first digit of the add-on number from number sets A or B;
— add-on delineator;
— second digit of the add-on number from number sets A or B;
— a right quiet zone.
The add-on has no right guard pattern. It does not have an explicit check digit. Checking is done through the
mix of the number sets (A or B) used for the two digits. The choice of number sets is linked to the value of the
add-on number as shown by Table 10.
Table 10 — Number sets for 2-digit add-on
Value of the add-on number Left-hand digit Right-hand digit
Multiple of 4 (00, 04, 08,…, 96) A A
Multiple of 4+1 (01, 05,…, 97) A B
Multiple of 4+2 (02, 06,…, 98) B A
Multiple of 4+3 (03, 07,…, 99) B B
Figure 5 shows an example of an UPC-A bar code symbol with 2-digit add-on.
Figure 5 — UPC-A bar code symbol with 2-digit add-on
4.2.3.5.3 Five-digit add-on symbol
The 5-digit add-on may be used in combination with an EAN-13, UPC-A or UPC-E symbol. The add-on is
positioned following the right quiet zone of the main symbol, and consists of the following:
— add-on guard pattern;
— first digit of the add-on number from number sets A or B;
— add-on delineator;
— second digit of the add-on number from number sets A or B;
— add-on delineator;
— third digit of the add-on number from number sets A or B;
— add-on delineator;
— fourth digit of the add-on number from number sets A or B;
— add-on delineator;
© ISO/IEC 2025 – All rights reserved
— fifth digit of the add-on number from number sets A or B;
— a right quiet zone.
The add-on has no right guard pattern. It does not have an explicit check digit. Checking is done through the
mix of the number sets (A or B) used for the five digits. A value v is determined by the following rules.
a) Sum the digits in positions 1, 3 and 5.
b) Multiply the result of a) by 3.
c) Sum the remaining digits (positions 2 and 4).
d) Multiply the result of c) by 9.
e) Sum the results of b) and d).
The value of v is the unit’s position (lowest-order digit) of the result of e).
EXAMPLE To calculate the value of v for the add on number 86104:
Step 1: 8 + 1 + 4 = 13
Step 2: 13 × 3 = 39
Step 3: 6 + 0 = 6
Step 4: 6 × 9 = 54
Step 5: 39 + 54 = 93
Step 6: v = 3
The number sets can then be determined by using Table 11.
Table 11 — Number sets for 5-digit add-on
v Number sets used for symbol characters
1 2 3 4 5
0 B B A A A
1 B A B A A
2 B A A B A
3 B A A A B
4 A B B A A
5 A A B B A
6 A A A B B
7 A B A B A
8 A B A A B
9 A A B A B
For the example, since v = 3, the sequence of number sets used to encode the value 86104 is B A A A B.
Figure 6 shows an example of an EAN-13 bar code symbol with 5-digit add-on.

© ISO/IEC 2025 – All rights reserved
Figure 6 — EAN-13 bar code symbol with 5-digit add-on
4.3 Dimensions and tolerances
4.3.1 Measurement basis
The dimensions of an EAN/UPC symbol may be referenced to a defined set of dimensions referred to as the
nominal size symbol. Historically, the predecessors of GS1 (see Annex C) specified the nominal size symbol
in terms of both inch-based and metric-based dimensions, with X dimensions of 0,013 inch (0,330 2 mm)
and 0,33 mm respectively. The precise conversion of the inch-based dimensions into metric units differs by
less than 0,1 % from the nominal metric dimensions. Either basis of measurement, applied consistently to
all dimensions of a symbol, is acceptable for the purposes of this document, although only the metric-based
dimensions are shown in 4.3 and in Annex E. Refer to Annex E for dimensioned drawings of nominal size
symbols.
4.3.2 Width of narrow element (X)
Historically, the nominal width of the narrow element of the nominal size EAN/UPC for scanning at point of
sale is 0,33 mm.
4.3.3 Bar height
The bar height of an EAN/UPC symbol with an X-dimension of 0,33 mm shall be:
— EAN-13, UPC-A and UPC-E symbols: 22,85 mm;
— EAN-8 symbols: 18,23 mm;
— add-on symbols: 21,90 mm.
In EAN-13, EAN-8, UPC-A, and UPC-E symbols the bars formi
...