# PDF417

> PDF417 is a stacked-linear 2D barcode from 1991, standardised as ISO/IEC 15438 — rows of bar-and-space codewords read like stacked 1D barcodes. It backs US and Canadian driver's licences and printed boarding passes, but needs several times more area than a QR code for the same data.

Source: https://useqr.app/glossary/pdf417 · Last reviewed 2026-08-21 · UseQR is free forever, MIT licensed, no signup.

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## Stacked, not matrix

PDF417 predates QR by three years — invented in 1991 by Ynjiun Wang at Symbol Technologies,
later ISO/IEC 15438. The name decodes its own geometry: *Portable Data File*, with each
[codeword](/glossary/codeword) drawn as **4 bars and 4 spaces across 17 units**. Symbols are
3 to 90 stacked rows flanked by start/stop bar patterns, which is why a PDF417 looks like a
dense 1D barcode that grew downward rather than a square mosaic. Being row-structured, it
can be read by sweeping laser scanners as well as cameras — a genuine advantage in 1991,
mostly irrelevant now that 2D imagers are universal.

Capacity peaks around **2,710 digits, 1,850 text characters or 1,108 bytes**, with
selectable Reed–Solomon security levels.

## Where you meet it

The back of every US and Canadian driver's licence carries a PDF417 encoding the AAMVA data
elements — name, date of birth, licence number — which is what bars and car-rental desks
scan. Printed (not mobile) boarding passes, shipping labels and some visa documents use it
too.

For anything new, its economics are poor: PDF417 typically needs **3–4 times the area** of
a [QR code](/glossary/qr-code) for the same payload, and phone camera apps rarely read it.
It persists where regulation froze it in place. See
[QR vs PDF417](/docs/basics/qr-code-vs-pdf417) for the comparison, and reach for a
[QR generator](/url-qr-code) otherwise.

## FAQ

### What is the barcode on the back of a driver's licence?
A PDF417 symbol. In the US and Canada it encodes the AAMVA standard's data elements — the same information printed on the front, in machine-readable form.

### Is PDF417 better than a QR code?
Rarely. It needs several times more area for the same data and phone cameras seldom read it. Its remaining strengths are legacy laser-scanner compatibility and mandated uses like licences.

### What does the 417 in PDF417 mean?
Each codeword is drawn as 4 bars and 4 spaces spanning 17 module widths — 4-1-7.

## Try it

- https://useqr.app/url
- https://useqr.app/validate