GS1 Prefix Check Calculator

About this calculator

GS1 barcode numbers — UPC-A, EAN-13, GTIN-8 and GTIN-14 — end in a check digit computed with a weighted modulo-10 algorithm: starting from the rightmost digit, alternating positions are multiplied by 3 and 1, the products summed, and the check digit is whatever makes that sum a multiple of 10. The leading digits also encode a GS1 company prefix, a block assigned to the manufacturer by a national GS1 member organization, which is how a scanner can trace a product back to its brand owner.

This calculator takes a barcode number, recomputes its check digit to confirm it's valid, and breaks out the company prefix block so you can see which registrant range it falls in. Retail and inventory staff verifying supplier data, e-commerce sellers listing products on marketplaces, and packaging designers laying out new barcodes use it to catch a mistyped digit or a malformed GTIN before it causes a scan failure at the register or a rejected marketplace listing.