A barcode is a method of representing data in a visual, machine-readable format. It consists of a series of bars of varying widths and spacings, which can be scanned by a barcode reader to automatically capture the data encoded within. Barcodes are used in a wide variety of applications, such as retail sales and inventory management, to quickly and easily capture and process information about products. The most common barcode format is the UPC (Universal Product Code) barcode, which is used primarily in retail settings to track product information such as price and inventory levels. Other common barcode formats include EAN (European Article Number), Code 39, and Code 128.