Need a U.P.C. Barcode? Choose a GS1 US GTIN or a GS1 Company Prefix based on your product line growth. Use the Barcode Estimator to help you determine how many barcodes you need and if your product is eligible for a GS1 US GTIN. If you want to identify locations with Global Location Numbers (GLNs), choose a GS1 Company Prefix.