Plain-English definitions for the terms you'll run into when working with barcodes and QR codes — from symbology to quiet zone to GTIN.
The technical term for a specific barcode encoding standard — CODE128, EAN-13 and QR Code are all different symbologies. Each defines its own rules for how characters map to bars, spaces or modules.
The blank margin required on either side of a barcode (or around a QR code). Scanners use this empty space to detect where the code starts and ends — cropping it too tight is one of the most common causes of a failed scan.
A final digit added to formats like EAN-13 and UPC-A, calculated from the preceding digits using a fixed formula. It lets a scanner detect a misread or mistyped digit rather than silently recording the wrong number. Use our check digit calculator to compute or validate one.
The umbrella term GS1 uses for the product identification numbers encoded in retail barcodes, including UPC-A (GTIN-12) and EAN-13 (GTIN-13). See our GS1 guide for how these numbers are assigned.
The nonprofit organization that administers global product barcode standards and assigns company prefixes, from which businesses generate their own range of GTINs.
The smallest single unit of a 2D code like a QR code — one of the individual black or white squares that make up the grid. A "module count" or "version" describes how many modules wide the whole code is.
Redundant data built into a QR code that lets it still be read correctly even if part of the code is damaged, dirty, or obscured. QR codes support four levels — L (7%), M (15%), Q (25%) and H (30%) — referring to the approximate percentage of the code that can be lost and still scan.
The three large square markers in the corners of a QR code. Scanners use them to instantly locate the code in an image and determine its orientation, even if the photo is taken at a slight angle.
1D (linear) barcodes like CODE128 or EAN-13 encode data in a single horizontal line of bars and spaces. 2D barcodes like QR Code, Data Matrix and PDF417 encode data across a two-dimensional grid, allowing far more data in the same physical space.
A dense, general-purpose linear symbology that can encode the full ASCII character set. The default choice for shipping labels and internal inventory codes that don't need to match a retail standard.
The standard retail barcode formats — EAN-13 is used across Europe and most of the world, UPC-A primarily in the US and Canada. Both encode a numeric product identifier plus a check digit.
A variant of the Interleaved 2 of 5 format sized and designed for printing on corrugated cardboard shipping cartons and pallets, tolerant of lower print quality than retail-shelf formats.
A compact 2D symbology that packs data into a very small square, commonly used to mark small electronics components or pharmaceutical packaging where space is extremely limited.
A 2D stacked symbology capable of storing large amounts of structured data, used on driver's licenses, boarding passes and shipping documents.
A standard file format for encoding contact information (name, phone, email, company). QR codes can encode a vCard directly so a phone offers to save it straight into the address book instead of just opening a link.
How tightly a symbology packs data relative to its physical size. Denser symbologies fit more information into less space but require higher-resolution printing to stay scannable.