UPC-A barcode
The 12-digit retail barcode scanned at point of sale across North America.
Also known as: UPC, GTIN-12, Universal Product Code
What is UPC-A?
UPC-A is the 12-digit linear barcode that carries a GTIN-12 and identifies one retail item at point of sale. The number is licensed through GS1, maps to exactly one product variant, and is the symbol every US retailer, Shopify POS, and Amazon expect on a consumer unit. The printed symbol is packaging artwork; the number behind it belongs in your catalog.
Encodes: A GTIN-12: eleven digits of identity plus one check digit. Numeric only.
How UPC-A is structured
A UPC-A reads left to right as a GS1 Company Prefix, an item reference, and a check digit. The first digit was historically called the number system character; today it is simply the first digit of the prefix, though a few values still carry meaning at the register.
| Part | Length | What it means |
|---|---|---|
| GS1 Company Prefix | 6 to 10 digits | Licensed from GS1 US. Identifies the brand owner. A leading 2 marks variable-weight items, 3 marks drugs (NDC), 4 is reserved for in-store use, 5 for coupons. |
| Item reference | 1 to 5 digits | Assigned by the brand to one product variant. Prefix plus item reference always total eleven digits. |
| Check digit | 1 digit | Calculated from the first eleven with the GS1 mod 10 algorithm. A scanner rejects a symbol whose check digit does not compute. |
Specifications
- Data
- 12 numeric digits (GTIN-12)
- Check digit
- GS1 mod 10, the 12th digit
- Nominal size (100%)
- 37.29 mm × 25.93 mm (1.469″ × 1.020″)
- Magnification range
- 80% to 200% of nominal
- X-dimension
- 0.330 mm at 100% (0.264 mm to 0.660 mm)
- Bar height
- 22.85 mm at 100%; do not truncate for POS scanning
- Quiet zones
- 9X on the left and right
- Symbol structure
- Left guard, six digits, center guard, six digits, right guard: 95 modules wide
- Scanning
- Omnidirectional at point of sale; add-on symbols (2- or 5-digit) allowed for periodicals and books
Dimensions are GS1 General Specifications targets. Confirm against the retailer’s current routing guide before a print run.
Where it is used
- Consumer units sold at retail point of sale in the United States and Canada
- The GTIN field on Amazon, Walmart Marketplace, and Google Shopping listings
- The barcode field on a Shopify or Shopify POS variant
- Item-level identification in retailer item setup and the EDI 832 catalog
Made once, by the designer, from a number the catalog owns
The GTIN is allocated from your GS1 prefix and stored on the product record. The symbol is generated once at the correct magnification, placed in the packaging file as vector art, and never rescaled in layout. It changes only when the product does. The system of record is the catalog; the artwork is downstream of it.
Retailers whose routing guides call for it
Each retailer page covers the transaction sets, labeling rules, and reported chargebacks behind the requirement.
Mistakes that cost money
Rescaling the symbol in the layout app
Stretching or shrinking a placed barcode breaks the bar-to-space ratio. Set the magnification when you generate it, then place at 100%.
Truncating the bars to fit a panel
Short bars remove the omnidirectional read at the register. If space is tight, go down to 80% magnification instead of cutting height.
Reversed or low-contrast colors
Red bars are invisible to a red laser scanner and metallic or reflective backgrounds scatter the beam. Black on white is the safe default; dark blue or green bars on white also read.
Recycled or resold GTINs
Amazon and the big-box retailers check the prefix against the GS1 registry. A code bought from a reseller carries another company’s prefix and gets flagged or rejected.
One GTIN across variants
Each size, color, and pack count needs its own GTIN. Sharing one across variants breaks POS pricing and inventory at every retailer that stocks more than one.
Design elements in the quiet zone
Text, borders, and photography inside the 9X margins stop the scanner from finding the edges of the symbol.
How Endless handles UPC-A
Endless keeps each variant’s GTIN on the canonical product record and pushes it into every channel and EDI catalog from there, so the code on the shelf, the marketplace listing, the 850 line, and the 856 item detail are the same number. Endless does not draw the packaging; it makes sure every system agrees on what the barcode says.
Frequently asked questions
What is the difference between UPC-A and EAN-13?
UPC-A carries a 12-digit GTIN-12; EAN-13 carries a 13-digit GTIN-13. A UPC-A with a leading zero is the same number as its EAN-13 form, and US point-of-sale systems have scanned both since 2005. Brands selling outside North America generally use EAN-13; brands selling only in the US and Canada use UPC-A.
Does every product variant need its own UPC?
Yes. A GTIN identifies one trade item as the retailer sells and stocks it, so each size, color, flavor, and pack count gets a distinct code. The case that holds those units gets a separate GTIN-14, carried in an ITF-14 or GS1-128 symbol.
Can I buy UPCs from a reseller instead of GS1?
You can, but resold codes carry the original licensee’s prefix, and marketplaces and retailers increasingly verify brand ownership against the GS1 registry. GS1 US licenses single GTINs and small prefixes, which removes the risk for a brand with a short catalog.
Will UPC barcodes still work after GS1 Sunrise 2027?
Yes. Sunrise 2027 is GS1’s target for retailers to be able to scan 2D codes such as QR and Data Matrix at point of sale. Linear UPC-A remains accepted, and most brands will dual-mark packaging during the transition rather than drop the UPC.
Related symbologies
Definitions in the glossary
- GTIN (Global Trade Item Number)→
A globally unique product identifier used across trading partners and marketplaces.
- UPC (Universal Product Code)→
The 12-digit barcode standard used to identify retail products at point of sale.
Browse the full barcode symbology guide.
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