UPCBay

What Is a Barcode?

A barcode is a machine-readable visual representation of a number — a series of lines and spaces that encode digits a scanner can read in milliseconds. In product commerce, barcodes encode a product's identifier (usually a UPC or EAN), linking the physical product to its digital record: price, inventory count, product details.

Real example

The barcodes you see on cereal boxes, books, and phone cases are encoding a 12-digit UPC or 13-digit EAN number. When a cashier scans your grocery item, the scanner reads those lines, resolves them to a product code, and looks up the price in the store's system. Same thing happens when Amazon's warehouse robot scans an inbound FBA shipment.

How a Barcode is used in e-commerce

  • Amazon requires a barcode (UPC or EAN) to create a new product listing.
  • Retail stores scan barcodes at checkout and during inventory counts.
  • Supply chain systems use barcodes at every stage: manufacturer → distributor → retailer → consumer.
  • FBA warehouses scan inbound shipments and outbound orders using barcodes (FNSKU for Amazon's internal system, UPC/EAN for catalog identification).

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Common questions

Related terms

UPC codeEAN codeGTINGS1Check digit