PDF417 Barcode Generator

What a PDF417 barcode is

PDF417 stands for Portable Data File 417. The name describes the symbol structure: each codeword is 17 modules wide and consists of 4 bars and 4 spaces, with the largest element spanning 6 modules.

PDF417 is defined in ISO/IEC 15438:2015. It is a continuous, multi-row, stacked 2D symbology — not a matrix like Data Matrix or QR Code, but a series of linear rows stacked one above the other. A reader decodes each row in sequence and assembles the full data payload. This design means a standard 1D laser scanner cannot read PDF417; the reader must be capable of scanning multiple rows and combining the result.

Each PDF417 symbol can contain 3 to 90 rows and 1 to 30 columns of data codewords, giving a highly configurable aspect ratio. The total width including quiet zones spans from 90X to 583X. This flexibility is why PDF417 is used on driving licences, where the card size and barcode footprint are fixed by the AAMVA standard, and on airline boarding passes, where the barcode must fit in a specific region of the document.

PDF417 technical specification

Capacity and symbol size

Error correction levels

PDF417 defines nine error correction levels numbered 0 through 8. At level 0, the symbol contains 2 error correction codewords. At level 8, the symbol contains 512 error correction codewords. More codewords for error correction means fewer codewords available for data, which reduces maximum capacity.

Level 0 is suitable for carefully controlled print and scanning environments where symbols are unlikely to be damaged. Level 5 or higher is appropriate for environments where symbols may be folded, printed on thermal paper that fades, or partially obscured. ISO/IEC 15438:2015 recommends a minimum of error correction level 2 for most applications.

Compact PDF417

Compact PDF417 is a variant that omits the right-side row indicator columns, reducing symbol width. It is used when label space is extremely constrained and the application can guarantee that the symbol will not be significantly damaged. Compact PDF417 is not as widely supported in scanner firmware as standard PDF417; verify reader support before deploying it.

When to use a PDF417 barcode

Driving licences in the United States and Canada. The AAMVA Driver's License/Identification Card Design Standard mandates PDF417 as the barcode symbology on the back of all US state and most Canadian province driver's licences and ID cards. The PDF417 barcode encodes the card holder's full name, address, date of birth, licence number, issuing jurisdiction and other fields defined by AAMVA. The standard references ISO/IEC 15438. This is the largest single deployment of PDF417 globally.

Airline boarding passes. IATA specifies PDF417 as one of the 2D barcode options for boarding pass bar codes, carrying passenger name, booking reference, origin, destination and seat assignment. Airport gate readers and checked-bag drop systems decode PDF417 as their primary or fallback format.

US Postal Service shipping labels. USPS uses PDF417 on shipping labels to carry tracking information that drives automated sortation and delivery confirmation.

Event ticketing and access control. PDF417 carries enough data for a full ticket payload including event, seat, gate and validity period in a single symbol, which makes it a practical choice for thermal-printed tickets that need to contain all information independently of a network lookup.

Healthcare patient wristbands. Patient identification wristbands in hospitals carry PDF417 to encode name, date of birth, medical record number and allergy alerts in a format readable by handheld scanners at the point of care.

High-density document encoding. Any application that needs to encode a full document or form in a single printable barcode — customs declarations, inspection certificates, laboratory orders — benefits from PDF417's 1,108-byte capacity at EC level 0.

Print requirements for PDF417

X-dimension. The X-dimension is the module width. The total symbol width is determined by the number of columns and the X-dimension. Use the largest X-dimension your label space allows, consistent with the scanner's minimum resolution specification.

Row height. ISO/IEC 15438:2015 specifies that the row height must be at least 3X. In practice, a row height of 5X to 10X improves scan reliability with laser-based readers that may not perfectly track between rows.

Quiet zones. PDF417 requires a quiet zone of at least 2X on the left and right and at least 2X above and below the symbol. Any border, art or text that encroaches on the quiet zone will cause the row indicators to be missed and the symbol to fail decoding.

Aspect ratio. Do not scale a PDF417 symbol unequally. The module width and row height must maintain their specified ratio. Non-uniform scaling produces rectangular modules instead of square ones and prevents correct decoding.

Substrate and contrast. PDF417 carries more data per symbol than most linear codes, so print contrast failures affect a larger proportion of the encoded codewords. Use high-contrast print media. Thermal printers must be calibrated so that dark bars do not bleed into adjacent spaces.

Troubleshooting: why your PDF417 barcode is not scanning

Row height too short. If the row height is less than 3X, many readers cannot distinguish individual rows and fail to decode the stacked structure. Increase the row height in the generator settings.

Missing quiet zone. PDF417 needs at least 2X of clear space on every side. Labels where the symbol is printed to the edge of the label stock will typically fail at the row indicator on the clipped side.

Error correction level too low for the print environment. A symbol printed at EC level 0 on thermal paper that curls or fades will fail to decode well before its useful life ends. Set a higher error correction level when durability is a concern.

Scanner cannot decode PDF417. Not all handheld scanners ship with PDF417 decoding enabled. Check the scanner's programming manual for a PDF417 enable instruction. Imager-based (area-array) scanners generally read PDF417 reliably; laser scanners may require multiple sweeps across the symbol height.

Non-uniform scaling. Stretching or compressing the symbol image alters module dimensions. Export from an SVG source and scale uniformly at the print stage.

Data exceeds capacity for the chosen configuration. If the encoded string is longer than the symbol's capacity at the chosen EC level, the generator will not produce a valid symbol. Either reduce the data, lower the error correction level, or increase the number of columns.

Binary data encoding error. When encoding binary data, ensure the generator is using Byte Compaction mode. Treating binary content as text will corrupt non-printable byte values.

PDF417 versus Data Matrix

PDF417 and Data Matrix both encode large amounts of data in a small area, but they serve different use cases and require different scanners.

Choose PDF417 when the application requires a variable-aspect-ratio symbol and the reading environment uses multi-row imaging scanners — as in driving licence verification terminals, boarding gate readers and postal sortation systems. Choose Data Matrix when the priority is the smallest possible footprint on a surface-marked part.