UPC / EAN Barcode FAQ & Tutorial
UPC/EAN Overview & Standards
 The UPC and EAN barcodes have been in use since the 1970s to encode
Global Trade Item Numbers (GTIN),
which uniquely identify a product for retail checkout or tracking purposes.
UPC, UCC, EAN, JAN, GTIN-8, GTIN-12 and GTIN-13,
ISBN and Bookland barcodes
are all created from the same symbology type, commonly known as the
UPC/EAN barcode.
GS1
DataBar (formerly RSS-14) is a smaller and more advanced barcode
type that may be used in retail checkout systems after
January 1, 2010.
To be fully GTIN compliant, all UPC and EAN numbers
should be stored in databases as 14-digit numbers and filled in with
zeros for the spaces to the left as shown in Fig: 1.
For example, a UPC-A barcode of 123456789012 would be represented as
00123456789012 in the database of a GTIN
compliant system. When encoding complete GTIN-14 numbers,
GS1 DataBar should be used.
DataBar Expanded should be used when it is necessary to encode additional
information such as weight, expiration dates and country of origin
or serial numbers.
Fig: 1. The various types
of UPC and EAN barcodes with their
GTIN capability
* GS1 DataBar (previously known as RSS-14) barcode encodes
13 digits with the required AI of 01 and a DataBar check digit. The
last digit of the GTIN-14 is a MOD 10 check digit
and is not encoded in the DataBar symbology. If the full 14-digit GTIN
is needed after reading the symbol, it may be generated with a
MOD10 calculation.
The
GS1
DataBar Barcode Symbology may be used in all retail checkout systems
after January 1, 2010.
** The UPC-E number of 02349036 displayed in the barcode equals the
00023400000900 UPC-A number after it is
expanded by the
UPCE suppression rules. Visual Basic source code to the
compression algorithm may be obtained by examining the UPCe7To11
function in the
IDAutomation Visual Basic Source Code, which is used to automate
printing for the
IDAutomation UPC
Barcode Font.
Printing UPC & EAN Barcodes
Several
Barcode
Integration Guides are available that suggest one or more barcode
printing options. These integration options should be examined to determine
whether to use barcode components, applications or fonts for the printing
of barcodes. A few of the
Barcode
Integration Guides offered include the following:
Featured Product:
The IDAutomation
UPC/EAN Font Advantage
Package is a single font used to create all UPC-A, UPC-E, EAN-8,
EAN-13, JAN, ISBN and Bookland barcodes. The font meets ANSI, ISO and
IEC 2000 specifications (ISO 15420:2000) and is supplied with several
barcode font tools,
plug-ins and source code samples for easy application integration.
When creating a single barcode, the
online font
encoder may be easily used with the
UPC/EAN Barcode
Font.
IDAutomation offers many other barcode generation products. For a
thorough evaluation of these products, visit the
Barcoding for Beginners FAQ & Tutorial.
The most common
method of reading barcodes is with a
barcode scanner.
Most barcode scanners recommended by IDAutomation perform keyboard emulation
and receive power from the USB port, so that no external power supply
is required. When a barcode is scanned using keyboard emulation, the
scanned data appears at the cursor as if it had been entered from the
keyboard.
Most barcode scanners have the ability to read UPC and EAN barcodes
by default, such as the hand-held
IDAutomation USB Barcode Scanner with DataBar. This scanner dependably
reads the IDAutomation
UPC/EAN Font when printed at any size allowed by GS1, which is from
12 to 32 points.
The character set for this symbology is best described by viewing
the UPC/EAN
Barcode Font Specifications. This site demonstrates how the symbols
are created from the characters found in the different character sets.
For easy application integration, IDAutomation provides several
Font Tools that
are free to use with IDAutomation barcode fonts. Therefore, references
to the character sets should not be necessary. When creating a single
barcode, IDAutomation recommends using the
Online Barcode Font Encoder.
The check digit is also referred to as the check character and checksum,
and it is always the last digit in the GTIN number. The manual calculations
described below are rarely necessary because IDAutomation provides several
font tools, plug-ins
and source code samples that are free to use with IDAutomation fonts,
which automatically format text
to the barcode fonts. Additionally, the check digit option in all
components
and applications
calculates and includes the checksum automatically.
A modulus 10 check digit is used for consistency verification in
all UPC-A, UPC-E, EAN-13 and EAN-8 barcode types. The check digit calculation
for UPC-E requires the original UPC-A number.
The UPC/EAN system uses a unique process to determine the check digit,
which is determined by the following modulus 10 algorithm:
- Add up the odd numbers (the rightmost character is odd) in the
digits and multiply them by 3.
- Add up the even numbers.
- The check digit is obtained by determining the smallest number,
that when added to the sum of steps 1 and 2, will produce a multiple
of 10. For example, the check digit for a UPC-A number of 12345678901
is 2 because (3*(1+3+5+7+9+1))+(2+4+6+8+0) = 98 and 98 + 2 =100.
- The check digit may be verified online by choosing the "MOD10"
button on our barcode
font encoder.
The following Visual Basic code is an example of calculating the
MOD10 check digit:
Factor = 3
WeightedTotal = 0
For I = Len(DataToEncode) To 1 Step -1
CurrentCharNum = Mid(DataToEncode, I, 1)
WeightedTotal = WeightedTotal + (CurrentCharNum * Factor)
Factor = 4 - Factor
Next I
I = (WeightedTotal Mod 10)
If I <> 0 Then
CheckDigit = (10 - I)
Else
CheckDigit = 0
End If
This Check Digit calculation may be tested by entering the number
into IDAutomation's Online
Font Encoder and choosing the MOD 10 option. GS1 also offers an
online
GTIN check digit calculator.
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