Every term you'll meet on a spec sheet, a GS1 document, or a printer's email — explained in plain English, with links to the tools and guides where each one matters.
A 2–4 digit GS1 prefix that declares what the data following it means: (01) = GTIN, (10) = batch/lot, (17) = expiry date, (21) = serial number. AIs let one barcode carry several structured fields, as in GS1-128 and GS1 Data Matrix.
Data containing letters and digits (and sometimes symbols). Symbologies differ in what they accept: EAN/UPC are numeric-only, Code 39 takes a limited character set, Code 128 and QR take the full range.
A machine-readable representation of data. 1D (linear) barcodes encode data in the widths of bars and spaces; 2D codes (QR, Data Matrix, PDF417) encode it in a grid of dark and light modules. See how barcodes work.
Deliberately thinning bars at artwork stage to compensate for ink spread on press, so the printed bars end up at their intended width. Exposed as a slider in our barcode generator — a prepress feature most free tools omit.
A heavy frame or horizontal bars printed around an ITF-14 symbol. It equalises printing-plate pressure on corrugated cartons and helps scanners reject partial reads.
The final digit of an EAN/UPC/GTIN, computed from the other digits with the Mod-10 algorithm. Scanners recompute it on every read and reject mismatches, catching typos before they reach the till. Worked example in our check digit guide.
The workhorse 1D symbology for non-retail use: compact, encodes the full ASCII set, no registration needed. The default choice for inventory, asset tags and internal logistics. Generator →
An older alphanumeric 1D symbology (A–Z, 0–9, a few symbols), still common in automotive, defence and ID applications. Less dense than Code 128 but extremely tolerant of low-quality printing. Generator →
A legacy numeric symbology with start/stop letters (A–D), still used by libraries, blood banks and some air waybills. Self-checking by design, which is why it survives in safety-critical niches.
The block of leading digits GS1 licenses to a company, from which it numbers its products. Marketplace GTIN checks validate that a product's prefix is registered to the brand claiming it — the reason resold UPC codes are risky.
The brightness difference between dark modules/bars and the light background. Scanners binarize the image, so insufficient contrast (or red bars under a red laser) reads as blank. Our generators score your exact color pair live.
A compact 2D symbology with an L-shaped finder pattern, readable at sizes down to ~2.5 mm. Dominant in direct part marking and pharmaceutical serialization. Compared with QR in Data Matrix vs QR. Generator →
The GS1 standard expressing a product's identity as a web URI — e.g. https://brand.com/01/09521234543213 — so one QR code works at both the checkout and a shopper's phone. Explained in our Digital Link guide; build one with the generator.
Engraving, etching or dot-peening a code straight onto a part (metal, plastic, glass) instead of a label — standard for electronics, aerospace and surgical instruments. Almost always Data Matrix, whose finder pattern tolerates the low contrast of etched marks.
Label printing that darkens heat-sensitive paper — no ink or ribbon. Cheap and clean for shipping labels, but the print fades with heat, sunlight and time; use thermal transfer for anything long-lived. See printing guide.
Printing both a 1D retail barcode and a 2D code (same GTIN) on a pack during the Sunrise 2027 transition, with code centers within 50 mm so checkout scanners don't double-ring. Our dual barcode generator builds the aligned block.
A QR encoding a short redirect URL on a vendor's domain, allowing the destination to be changed and scans to be counted — at the cost of depending on that vendor's server and your subscription. Contrast with static QR; full discussion in do QR codes expire.
The 13-digit worldwide retail barcode (GTIN-13). The first digits form a GS1 country-of-registration prefix; the last is the check digit. Generator →
A short 8-digit EAN for packages too small for EAN-13. Allocated sparingly by GS1 because the numbering space is limited.
The modern Data Matrix error-correction standard, using Reed–Solomon codes. If a spec says "Data Matrix ECC 200", it means the current standard rather than the obsolete ECC 000–140 variants.
Redundancy built into 2D codes so damaged or covered modules can be reconstructed. QR offers four levels — L ≈ 7%, M ≈ 15%, Q ≈ 25%, H ≈ 30% recoverable — and embedding a logo spends this budget, which is why our meter raises EC automatically.
The fixed geometry a scanner locates first: the three corner squares of a QR code, or the solid L-border of a Data Matrix. Damage to finder patterns is far more fatal than damage to data modules.
A non-printing control character marking a symbol as GS1-formatted and separating variable-length AI fields. Generators that handle GS1 properly insert FNC1 for you — ours does, natively, in GS1 Data Matrix and DataBar.
Amazon's internal product identifier ("Fulfillment Network SKU"), printed as a Code 128 label on FBA inventory when the manufacturer barcode isn't used. Distinct from your GTIN/UPC.
The global not-for-profit that runs the GTIN numbering system, the barcode standards built on it (EAN, UPC, GS1-128, DataBar, GS1 Data Matrix, Digital Link), and national member organisations that license numbers to companies.
Code 128 carrying GS1 Application Identifiers — the standard way to put GTIN + batch + expiry on logistics labels and cases. Generator →
A family of compact GS1 symbols for items too small for EAN — loose produce, coupons, small cosmetics. The Expanded variant carries AIs beyond the GTIN. Generator →
Data Matrix with GS1 AI formatting (FNC1-led), mandated for unit-level pharmaceutical serialization in many markets: GTIN, batch, expiry and serial in a fingernail-sized square. Generator →
Global Trade Item Number — the umbrella term for GS1 product numbers: GTIN-12 (UPC-A), GTIN-13 (EAN-13), GTIN-8 (EAN-8) and GTIN-14 (case level, rendered as ITF-14). "Does Amazon need a GTIN?" — usually yes.
The slightly longer bar groups at the start, middle and end of an EAN/UPC symbol. They delimit the code, separate its halves, and let scanners detect reading direction — which is how upside-down scans still work.
The digits printed beneath a barcode. Not decoration: when a symbol won't scan, the cashier keys the HRI. GS1 specifies its presence and placement for retail symbols.
A scanner that photographs the code and decodes the image in software — the technology in every smartphone and modern retail scanner. Reads both 1D and 2D symbols, unlike a laser scanner.
The tendency of printed bars to fatten as ink soaks and squashes into the substrate, narrowing the spaces between them until the code fails. Countered at artwork stage with Bar Width Reduction.
The international book number — encoded at retail as an EAN-13 beginning 978 or 979. A book's barcode is just its ISBN in EAN clothing.
The 14-digit Interleaved 2 of 5 symbol used on shipping cartons (GTIN-14), printed large with bearer bars to survive corrugate. Generator →
A scanner sweeping a red laser line and reading reflected brightness — fast and long-ranged, but inherently 1D-only and blind to red ink and inverted colors. The installed base of laser checkouts is why retail still leads with EAN/UPC.
Any symbology encoding data purely in horizontal bar/space widths: EAN, UPC, Code 128, Code 39, ITF, MSI, Codabar. Vertical height adds scan redundancy, not data.
An EAN/UPC's size as a percentage of nominal (100% = 37.29 × 25.93 mm for EAN-13). GS1 permits 80%–200%; below 80% scanning reliability collapses. Details in size requirements.
The atomic unit of a code: the narrowest bar/space width in 1D (the X-dimension), or one grid cell in a QR/Data Matrix. Everything else is sized in multiples of it.
A numeric-only legacy symbology still found on warehouse shelf-edge labels. No retail role; mostly encountered when maintaining older inventory systems.
Reading a barcode regardless of its rotation — what checkout scanners do with crossing laser patterns or imaging. It depends on full bar height, which is why truncation breaks it.
A stacked 2D symbology (rows of 1D-like codewords) holding ~1.1 KB. The format on US driver's licences, boarding passes and many shipping documents. Generator →
A simple binary symbology read by packaging-line cameras to verify the right carton/leaflet is on the line. Encodes 3–131070; never consumer-facing.
The checkout — registers, scanners and software. "2D at POS" is shorthand for the Sunrise 2027 goal of checkouts reading QR/Data Matrix.
The dominant consumer 2D symbology: three-square finder pattern, up to 7,089 digits, selectable error correction, native support in every phone camera. Generator →
The size step of a QR symbol, from Version 1 (21×21 modules) to Version 40 (177×177). More data → higher version → finer modules at the same print size, which is why long URLs need bigger codes.
The mandatory blank margin around a symbol — how the scanner finds its edges. EAN-13 requires 11 modules left / 7 right; QR requires 4 on all sides. Cropping it is the classic "perfect-looking barcode that won't scan."
The error-correction mathematics inside QR, Data Matrix and PDF417 (also CDs and deep-space comms). It's what lets a code lose up to ~30% of its area — or host a logo — and still decode.
The web service a Digital Link URI points at, which redirects scans to product information. Brands host their own or use GS1's canonical resolver at id.gs1.org.
A per-unit identifier carried under Application Identifier 21, the backbone of pharma serialization and unit-level traceability.
Serial Shipping Container Code — the 18-digit GS1 identifier for a specific logistics unit (one pallet, one carton), usually carried in GS1-128 under AI (00).
A QR encoding its final data directly in the pattern — no intermediary server, nothing to expire, working as long as the destination exists. Everything this site generates is static, by design.
The GS1 initiative for retailers to be able to scan 2D barcodes at point of sale by the end of 2027, transitioning packaging toward Digital Link QR codes via a dual-marking period. Plain-English overview in our guide.
Scalable Vector Graphics — barcodes described as geometry rather than pixels, so they print razor-sharp at any size. The format to hand to printers; both our generators export it.
A barcode "language": the rules mapping data to bars or modules. EAN-13, Code 128, QR and Data Matrix are symbologies. Choosing one is the question our picker guide answers.
Label printing that melts ribbon resin onto the label — durable for years against heat, light and abrasion. The right choice for asset tags and outdoor labels; compare direct thermal.
The alternating dark/light line running between a QR code's finder squares, letting the decoder establish the module grid even when the print is slightly distorted.
Cutting a retail barcode's height to fit a design. Prohibited by GS1 for EAN/UPC because it defeats omnidirectional scanning — a frequent cause of mystery checkout failures.
The 12-digit North American retail barcode (GTIN-12); technically an EAN-13 with a leading zero. Generator → · EAN vs UPC →
A compressed 6-digit rendering of certain UPC-A numbers (zero-suppressed) for very small packages like gum and cigarettes.
The standard digital business-card format (name, organisation, phone, email). Encoded in a QR, it adds a contact to the scanner's phone in one tap. Generator →
Formal print-quality measurement against ISO 15416 (1D) / 15415 (2D), grading symbols A–F with a calibrated verifier device. Retail compliance programs may require a minimum grade — distinct from simply "it scanned on my phone."
The width of a symbol's narrowest element — the base unit all bar widths are multiples of. Printer resolution and scanner optics both impose minimum X-dimensions, which is where minimum size rules come from.
Missing a term you expected? The guides cover most of these in depth, and the which-barcode picker applies them to real decisions. Back to top ↑