PDF417 Generator

Stacked 2D barcode used on identity cards, boarding passes and transport documents.

How PDF417 is structured

PDF417 is a stacked linear symbology: up to 90 rows, each row a strip of 17-module codewords with its own start and stop pattern and left and right row indicators. The reader uses those indicators to reassemble the rows in order, which is why a symbol can be tall and narrow or short and wide. Capacity reaches about 1,850 text characters or 2,710 digits, far more than any 1D symbol.

PDF417 check digit

Error correction is Reed-Solomon, selectable across nine levels from 0 to 8. Level 0 adds two correction codewords; level 8 adds 512, and the level chosen determines how much of the symbol can be destroyed before it stops decoding. On top of that, the row indicators are themselves checkable, so a row read out of order is detected rather than silently misassembled.

PDF417 compared with Data Matrix

Data Matrix is denser for small payloads and suits direct part marking; PDF417 is the choice when a document has to carry a long structured record — a driving licence, a boarding pass, a customs form. Aztec Code packs the same kind of data more compactly but is less common on government documents. Compare the Data Matrix generator page for the same breakdown of structure, check digit and use cases.

Common PDF417 problems

The X-dimension is below the reader's floor

PDF417 rows are narrow strips, and a symbol printed small enough to look neat often cannot be resolved by a handheld imager. Enlarge the symbol, reduce the data, or accept more rows rather than shrinking the module width.

The aspect ratio does not fit the document

Row count and column count are settable, and an awkward combination produces a symbol that is technically valid and practically unreadable. Tune the row count first — that changes the shape without changing capacity.

Damage exceeds the chosen error correction level

A crease or a punch across several rows can overwhelm a low EC level. Raise the level for documents that are folded, laminated or handled daily, accepting the larger symbol that comes with it.

Where PDF417 is used

Not sure this is the right symbology? The barcode format guide groups every supported 1D and 2D format by industry with its character set and limits.