Editing Universal Product Code (section)

== Variations ==
UPC in its most common usage technically refers to UPC-A.

Other variants of the UPC exist:
* UPC-B is a 12-digit version of UPC with no check digit, developed for the [[National Drug Code | National Drug Code (NDC)]] and National Health Related Items Code.<ref>{{cite web|url=http://www.healthdata.gov/dataset/nhric-national-health-related-items-code|website=HealthData|title=NHRIC (National Health Related Items Code)|publisher=U.S. Department of Health & Human Services|access-date=12 October 2015|archive-date=8 March 2021|archive-url=https://web.archive.org/web/20210308015954/https://healthdata.gov/dataset/nhric-national-health-related-items-code|url-status=dead}}</ref>{{failed verification|date=February 2017}}  It has 11 digits plus a 1-digit product code, and is not in common use.<ref name="adams1">{{cite web |url=https://www.adams1.com/upccode.html |title=Bar Code 1: A Web Of Information About Bar Code UPC and EAN Bar Code Page |date=20 June 2013 |work=Adams Communications |access-date=10 July 2019 |archive-date=8 March 2021 |archive-url=https://web.archive.org/web/20210308005638/https://www.adams1.com/upccode.html |url-status=live }}</ref>
* UPC-C is a 12-digit code with a product code and a check digit; not in common use.<ref name="adams1" />
* UPC-D is a variable length code (12 digits or more) with the 12th digit being the check digit. These versions are not in common use.
* UPC-E is a 6-digit code, that has its equivalent in UPC-A 12-digit code with number system 0 or 1.
* [[EAN 2|UPC-2]] is a 2-digit supplement to the UPC used to indicate the edition of a magazine or periodical.
* [[EAN 5|UPC-5]] is a 5-digit supplement to the UPC used to indicate suggested retail price for books.

=== UPC-E ===
To allow the use of UPC barcodes on smaller packages, where a full 12-digit barcode may not fit, a zero-suppressed  version of UPC was developed, called UPC-E, in which the number system digit, all trailing zeros in the manufacturer code, and all leading zeros in the product code, are suppressed (omitted).<ref>{{cite web|title=UPC-A Symbology – UPC-E background information and UPC-A to UPC-E conversion|url=http://www.barcodeisland.com/upce.phtml|website=barcodeisland.com|access-date=21 January 2013|archive-date=26 February 2020|archive-url=https://web.archive.org/web/20200226110541/http://www.barcodeisland.com/upce.phtml|url-status=dead}}</ref> This symbology differs from UPC-A in that it only uses a 6-digit code, does not use M (middle) guard pattern, and the E (end) guard pattern is formed as ''space-bar-space-bar-space-bar'', i.e. UPC-E barcode follows the pattern SDDDDDDE. The way in which a 6-digit UPC-E relates to a 12-digit UPC-A, is determined by UPC-E numerical pattern and UPC-E parity pattern. It can only correspond to UPC-A number system 0 or 1, the value of which, along with the UPC-A check digit, determines the UPC-E parity pattern of the encoding. With the manufacturer code digits represented by M's, and product code digits by P's, then:

{| class="wikitable" style="text-align:center;"
! Last UPC-E digit !! UPC-E numerical pattern !! UPC-A equivalent !! Available product numbers
|-
| 0 || style="font-family:monospace;" | MMPPP0 || style="font-family:monospace;" | 0 or 1 + MM000-00PPP + check digit || style="font-family:monospace;" | PPP = 000-999
|-
| 1 || style="font-family:monospace;" | MMPPP1 || style="font-family:monospace;" | 0 or 1 + MM100-00PPP + check digit || style="font-family:monospace;" | PPP = 000-999
|-
| 2 || style="font-family:monospace;" | MMPPP2 || style="font-family:monospace;" | 0 or 1 + MM200-00PPP + check digit || style="font-family:monospace;" | PPP = 000-999
|-
| 3 || style="font-family:monospace;" | MMMPP3 || style="font-family:monospace;" | 0 or 1 + MMM00-000PP + check digit || style="font-family:monospace;" | PP = 00-99
|-
| 4 || style="font-family:monospace;" | MMMMP4 || style="font-family:monospace;" | 0 or 1 + MMMM0-0000P + check digit || style="font-family:monospace;" | P = 0-9
|-
| 5 || style="font-family:monospace;" | MMMMM5 || style="font-family:monospace;" | 0 or 1 + MMMMM-00005 + check digit || style="font-family:monospace;" | 5 = P
|-
| 6 || style="font-family:monospace;" | MMMMM6 || style="font-family:monospace;" | 0 or 1 + MMMMM-00006 + check digit || style="font-family:monospace;" | 6 = P
|-
| 7 || style="font-family:monospace;" | MMMMM7 || style="font-family:monospace;" | 0 or 1 + MMMMM-00007 + check digit || style="font-family:monospace;" | 7 = P
|-
| 8 || style="font-family:monospace;" | MMMMM8 || style="font-family:monospace;" | 0 or 1 + MMMMM-00008 + check digit || style="font-family:monospace;" | 8 = P
|-
| 9 || style="font-family:monospace;" | MMMMM9 || style="font-family:monospace;" | 0 or 1 + MMMMM-00009 + check digit || style="font-family:monospace;" | 9 = P
|}

For example, a UPC-E 654321 may correspond to the UPC-A 065100004327 or 165100004324, depending on the UPC-E parity pattern of the encoded digits, as described next:

{| class="wikitable" style="text-align:center;"
! UPC-A <br />check digit 
! UPC-E parity pattern for UPC-A<br />
number system 0
! UPC-E parity pattern for UPC-A<br />
number system 1
|-
| 0 || style="font-family:monospace;" | EEEOOO || style="font-family:monospace;" | OOOEEE
|-
| 1 || style="font-family:monospace;" | EEOEOO || style="font-family:monospace;" | OOEOEE
|-
| 2 || style="font-family:monospace;" | EEOOEO || style="font-family:monospace;" | OOEEOE
|-
| 3 || style="font-family:monospace;" | EEOOOE || style="font-family:monospace;" | OOEEEO
|-
| 4 || style="font-family:monospace;" | EOEEOO || style="font-family:monospace;" | OEOOEE
|-
| 5 || style="font-family:monospace;" | EOOEEO || style="font-family:monospace;" | OEEOOE
|-
| 6 || style="font-family:monospace;" | EOOOEE || style="font-family:monospace;" | OEEEOO
|-
| 7 || style="font-family:monospace;" | EOEOEO || style="font-family:monospace;" | OEOEOE
|-
| 8 || style="font-family:monospace;" | EOEOOE || style="font-family:monospace;" | OEOEEO
|-
| 9 || style="font-family:monospace;" | EOOEOE || style="font-family:monospace;" | OEEOEO
|}

{| class="wikitable" style="text-align:center; background-color:#80A080;"
|+ Encoding table for UPC-E barcode pattern SDDDDDDE
! rowspan="2" | S<br/>(start)
! colspan="10" | O<br/>(odd parity digit)
! colspan="10" | E<br/>(even parity digit)
! rowspan="2" | E<br/>(end)
|-
! 0 !! 1 !! 2 !! 3 !! 4 !! 5 !! 6 !! 7 !! 8 !! 9 !! 0 !! 1 !! 2 !! 3 !! 4 !! 5 !! 6 !! 7 !! 8 !! 9
|- valign="top"
| [[File:UPC-E S.svg|10x250px]] || style="font-size:70%;" | [[File:UPC-E 0ow.svg|21x235px]]<br />3-2-1-1 || style="font-size:70%;" | [[File:UPC-E 1ow.svg|21x235px]]<br />2-2-2-1 || style="font-size:70%;" | [[File:UPC-E 2ow.svg|21x235px]]<br />2-1-2-2 || style="font-size:70%;" | [[File:UPC-E 3ow.svg|21x235px]]<br />1-4-1-1 || style="font-size:70%;" | [[File:UPC-E 4ow.svg|21x235px]]<br />1-1-3-2 || style="font-size:70%;" | [[File:UPC-E 5ow.svg|21x235px]]<br />1-2-3-1 || style="font-size:70%;" | [[File:UPC-E 6ow.svg|21x235px]]<br />1-1-1-4 || style="font-size:70%;" | [[File:UPC-E 7ow.svg|21x235px]]<br />1-3-1-2 || style="font-size:70%;" | [[File:UPC-E 8ow.svg|21x235px]]<br />1-2-1-3 || style="font-size:70%;" | [[File:UPC-E 9ow.svg|21x235px]]<br />3-1-1-2 || style="font-size:70%;" | [[File:UPC-E 0ew.svg|21x235px]]<br />1-1-2-3 || style="font-size:70%;" | [[File:UPC-E 1ew.svg|21x235px]]<br />1-2-2-2 || style="font-size:70%;" | [[File:UPC-E 2ew.svg|21x235px]]<br />2-2-1-2 || style="font-size:70%;" | [[File:UPC-E 3ew.svg|21x235px]]<br />1-1-4-1 || style="font-size:70%;" | [[File:UPC-E 4ew.svg|21x235px]]<br />2-3-1-1 || style="font-size:70%;" | [[File:UPC-E 5ew.svg|21x235px]]<br />1-3-2-1 || style="font-size:70%;" | [[File:UPC-E 6ew.svg|21x235px]]<br />4-1-1-1 || style="font-size:70%;" | [[File:UPC-E 7ew.svg|21x235px]]<br />2-1-3-1 || style="font-size:70%;" | [[File:UPC-E 8ew.svg|21x235px]]<br />3-1-2-1 || style="font-size:70%;" | [[File:UPC-E 9ew.svg|21x235px]]<br />2-1-1-3 || style="font-size:70%;" | [[File:UPC-E E.svg|18x250px]]
|}

UPC-E 654321 with "EOEOEO" parity pattern (UPC-A 065100004327) would be encoded as

:1-1-1 &nbsp;4-1-1-1 &nbsp;1-2-3-1 &nbsp;2-3-1-1 &nbsp;1-4-1-1 &nbsp;2-2-1-2 &nbsp;2-2-2-1 &nbsp;1-1-1-1-1-1.

The barcode would look like this: 
[[File:UPC-E-654321.png|center]]

=== EAN-13 ===
{{Main|International Article Number}}

The [[International Article Number|EAN-13]] was developed as a [[subset|superset]] of UPC-A, adding an extra digit to the beginning of every UPC-A number. This expanded the number of unique values theoretically possible by ten times to 1 trillion. EAN-13 barcodes also indicate the country in which the company that sells the product is based (which may or may not be the same as the country in which the good is manufactured). The three leading digits of the code determine this, according to the [[List of GS1 country codes|GS1 country codes]]. Every UPC-A code can be easily converted to the equivalent EAN-13 code by prepending 0 digit to the UPC-A code. This does not change the [[check digit]]. All [[point-of-sale]] systems can now understand both equally.

[[EAN-8]] is an 8-digit variation of the EAN barcode.

UPC usage notes:
* All products marked with an EAN will be accepted in North America currently, in addition to those already marked with a UPC.
* Products with an existing UPC do not have to be re-marked with an EAN.
* In North America, the EAN adds 30% more codes, mainly by adding digits 10 through 12 to the UPC digits 00 through 09. This is a powerful incentive to phase out the UPC.