Barcode Glossary
The barcode industry has a term for everything, and often three terms for the same thing. This barcode glossary explains what each one actually means in plain English, so you can work out what a retailer is asking you for.
Can’t find a term? Ask us, and we’ll add it.
Retail barcode numbers
Barcode
An image that holds a small amount of information a scanner or phone app can read instantly. On retail products, it’s almost always a 12- or 13-digit number encoded as bars.
Barcode package
A purchase option that combines the barcode number and barcode images into a single transaction, usually with a guarantee certificate and registration included.
Barcode registration
An optional service that links your product details to your number so they appear when someone scans the number with a phone app. There is no compulsory registration database for barcode numbers anywhere in the world.
Check digit
The final digit of a barcode number, calculated from the digits before it. If any digit is keyed in wrong, the check digit no longer matches, and the system rejects the entry. You can test yours with our GTIN validator.
Company prefix
The block of digits that stays the same across all of a company’s barcode numbers. The more digits a company has, the shorter its prefix, because the remaining digits must fit within the 13-digit total. See our company prefix page.
Country code
The first two or three digits of a retail barcode number that indicate which GS1 member organisation issued it. A common misconception is that this shows where the product was made. It doesn’t — it only shows where the number came from.
EAN-8
A shortened eight-digit retail barcode for products too small to carry a full EAN-13, such as cigarette packets or small cosmetics. Also called GTIN-8.
EAN-13
European Article Number. The 13-digit retail barcode used on products almost everywhere in the world. Only the USA and Canada favour UPC-A instead, and stores there still accept EAN-13. The term refers to both the number and the barcode format.
GLN
Global Location Number. A 13-digit number that identifies a location or a business rather than a product, used in EDI messages and supplier onboarding. See our GLN numbers page.
GTIN
Global Trade Item Number. The umbrella term for any retail barcode number in the GS1 system: GTIN-13 (EAN-13), GTIN-12 (UPC-A), GTIN-8 (EAN-8) and GTIN-14 (ITF-14).
ITF-14
Interleaved Two of Five. A large barcode printed on outer cartons rather than on retail packaging, built from the product’s EAN-13 number plus a leading digit indicating how many items are in the case. Used for stock movement, never at a checkout. See carton barcodes.
SSCC
Serial Shipping Container Code. An 18-digit number identifying an individual pallet or shipping unit. Every pallet needs its own SSCC, so they’re consumed in volume rather than bought once.
UPC-A
Universal Product Code. The 12-digit retail barcode used predominantly in the USA and Canada, though accepted worldwide. UPC-A numbers are effectively a subset of EAN-13: add a leading zero, and you have the same number in 13-digit form.
UPC-E
A compressed six-digit version of UPC-A for small packaging. It suppresses zeros from the full number and expands back to the full UPC-A when scanned.
Books, magazines and media
EAN-5 and EAN-2 add-on codes
The small extra barcodes printed beside a main barcode. EAN-5 carries a price and appears on books; EAN-2 carries an issue number and appears on magazines.
ISBN number
International Standard Book Number. A 13-digit number beginning 978 or 979, issued to books by a national ISBN agency. See book barcodes.
ISBN barcode
The printed barcode generated from an ISBN, using EAN-13 symbology with the ISBN shown in text above the bars.
ISSN number
International Standard Serial Number. An eight-digit number issued to magazines and other periodicals that converts to a 13-digit barcode.
ISSN barcode
The 13-digit barcode produced from an ISSN, encoded in EAN-13 symbology and printed on magazines and periodicals.
Barcode formats and symbologies
Symbology
The way a barcode encodes its data — effectively the barcode’s language. EAN-13, Code 128 and QR are all different symbologies. Often used interchangeably with “format”.
Encoding
The information a barcode image is generated from. For an EAN-13 barcode, the encoding is the 13-digit number.
Parity
The pattern of black and white spaces used to represent each digit. Each digit uses a different combination, and the sequence of patterns is what allows a scanner to read a barcode in either direction.
Asset tracking barcodes
Sequential numbers encoded in Code 39 or Code 128 and attached to business equipment to track what goes in and out. Libraries use the same approach for lending.
Code 39
An older symbology that encodes letters and numbers. It has low data density, so a Code 39 barcode occupies more width than alternatives and isn’t ideal for small labels.
Code 128
A denser symbology that encodes the full ASCII character set, including letters, numbers and punctuation. It fits more data in less space than Code 39, making it the better choice for small items.
GS1-128
Code 128 is used within the GS1 system, with application identifiers that tell the receiving system what each part of the data means — batch number, expiry date, weight and so on. Common on logistics labels.
QR codes and 2D barcodes
2D barcode
Also called a matrix barcode. A barcode that encodes information both vertically and horizontally rather than in bars alone, allowing it to hold far more data. See our 2D barcodes page.
QR code
Quick Response code. The most common 2D barcode, originally developed for Toyota’s production line and now used worldwide, most often to send a phone to a web address. See QR code services.
Static QR code
A QR code with the destination encoded directly into the image. It can’t be changed after printing — if you need a different destination, you need a new code.
Dynamic QR code
A QR code that points to a redirect service rather than straight to your page, so the destination can be changed at any time without reprinting. It also allows scan tracking.
Data Matrix
A compact 2D barcode used in engineering and manufacturing to identify individual components, often marked directly onto the part.
Aztec code
A 2D barcode with a distinctive square bullseye at its centre, used widely for transport ticketing.
PDF417
A stacked 2D barcode used on identification cards, boarding passes and e-tickets, capable of holding several hundred characters.
MaxiCode
A dotted 2D barcode used by postal and courier services. Its central bullseye allows a scanner to read it while the parcel moves along a conveyor.
vCard
A text format that encodes contact details into a QR code, so scanning it adds the contact straight to a phone’s address book.
vCalendar
A text format that encodes an event into a QR code, so scanning it adds the event to a phone’s calendar.
GS1 Digital Link
A newer standard that turns a product’s GTIN into a web address, so a single 2D code can serve both a checkout scanner and a shopper’s phone. It underpins the industry shift towards 2D codes on retail packaging.
Print specifications and quality
Specifications
The dimensions and print requirements a barcode must meet to be officially accepted. Retailers vary in how strictly they enforce them — smaller stores tend to be more relaxed. See our specifications page.
Bar height
The height of the shortest bars in the barcode, measured excluding the numbers printed underneath.
Bar width
The total width of the bars, excluding the quiet zones on either side.
X-dimension
The width of the narrowest bar or space in the barcode. Every other measurement is a multiple of it, so the X-dimension effectively sets the barcode’s overall size.
Magnification
How large is the printed barcode relative to its nominal size, expressed as a percentage? An EAN-13 can be printed at 80%-200% and remain within specification.
Quiet zone
The clear white space required on either side of the bars. Without it, a scanner can’t tell where the barcode begins and ends. A ‘>’ symbol is sometimes printed to mark the outer edge.
Human-readable numerals
The digits printed below the bars, so the number can be typed in manually if the barcode won’t scan.
Print contrast
The difference in reflectance between the bars and the background. Scanners need dark bars on a light background; some colour combinations, particularly red bars, don’t provide enough contrast to read at all.
Verification
A test scan of a barcode as it will actually be printed, assessing how reliably it will read. Some larger retailers require a verification report before listing a product.
Grade
The score a verification report gives a barcode, from A down to F. Most retailers asking for verification want a C or better.
Organisations and compliance
GS1
Global Standards One. The not-for-profit organisation that maintains barcode standards worldwide. Barcode numbers can be licensed from GS1, which generally involves a joining fee and annual membership fees.
UCC
Uniform Code Council. The American body that sold 12-digit barcode numbers outright before merging into GS1 US in the late 1990s. Numbers originally issued by the UCC sit outside GS1’s licensing, which is why they can be resold for a one-off cost.
Reseller barcode
A barcode number sold outright by a supplier other than GS1, with no annual fees. Accepted by the large majority of retailers worldwide, with some exceptions listed on our barcode acceptance page.
EDI
Electronic Data Interchange. The standardised electronic exchange of purchase orders, invoices and shipping notices between trading partners. EDI onboarding typically involves a retailer requesting a GLN from a supplier.
GDSN
Global Data Synchronisation Network. The GS1 system through which suppliers publish product data to retailers. It validates numbers against the GS1 registry, so reseller numbers can’t be used with it.
Verified by GS1
A GS1 lookup service that checks whether a barcode number is licensed to the company using it. Retailers who run this check need GS1-issued numbers.
FNSKU
Fulfilment Network Stock Keeping Unit. Amazon’s own internal product label for items held in its warehouses. It isn’t a retail barcode and doesn’t replace one. See barcodes for Amazon.
GTIN exemption
Amazon’s process for listing a product without a barcode number. It’s granted on a case-by-case basis and can be withdrawn, so most sellers are better off with a proper number.
Still stuck on a term?
If a retailer has used a term that isn’t here, send us the message they sent you. We answer our own emails and reply within one business day.
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