PDf417 width illustrationPDF 417 codeword illustration
The diagram at left shows the relationship of an individual codeword to a PDF417 barcode as a whole. The diagram at right shows a single codeword broken down into its 4 bars and spaces, as well as its 17 units of width. It is possible to make 929 unique codewords using this pattern, each of which can represent numerals, letters, or other data.
PDF417 is a widely used format for 2D barcodes that contains data in “codewords” that are stacked into multiple columns to make a machine-readable pattern. Each codeword is a horizontal strip made up of four dark bars alternating with four white spaces. It is divided into 17 units of identical width, each of which can be either black or white. The number 417 in the name comes from the 4 bars and spaces and the 17-unit total length of each codeword.

For check scanners, PDF417 is important because it is the standard barcode format for most state-issued driver’s licenses and ID cards, including all that are issued in compliance with the federal Real ID Act. Many banks and credit unions have begun using check scanners to capture images of customer IDs at the teller window, making the ability to identify and read PDF417 format a key capability for data extraction and validation.