UPC-E is a variation of UPC-A which allows for a more compact barcode by eliminating âextraâ zeros. Since the resulting UPC-E barcode is about half the size as an UPC-A barcode, UPC-E is generally used on products with very small packaging where a full UPC-A barcode couldnât reasonably fit. Not all UPC-A Numbers can be converted to UPC-E.