# Aztec code

> Aztec is a 2D matrix barcode with a square bullseye finder at its centre, defined in ISO/IEC 24778. It needs no quiet zone at all, which suits cramped tickets, and it dominates transport: rail e-tickets and IATA-standard mobile boarding passes are typically Aztec symbols.

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

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## The bullseye in the middle

Where a QR code locates itself with three corner
[finder patterns](/glossary/finder-pattern), Aztec (ISO/IEC 24778) puts one concentric
square bullseye dead centre and grows data outward in rings. Two consequences follow.
First, **no [quiet zone](/glossary/quiet-zone) is required** (the only major 2D symbology
where that is true), so the code can run right against borders, text and artwork on a
cramped ticket layout. Second, the reader parameters live in a ring around the bullseye
rather than in fixed corners, letting error correction be tuned in fine steps instead of
QR's four levels.

Symbols range from **15 × 15** (compact) to **151 × 151** modules, holding up to **3,832
digits or 1,914 bytes**.

## Why your boarding pass is an Aztec

The IATA bar-coded boarding pass (BCBP) standard specifies Aztec (alongside QR and Data
Matrix) for mobile passes, and airlines overwhelmingly render Aztec; most European rail
operators (Deutsche Bahn, SNCF, Trenitalia among them) use it for e-tickets. It scans
well from phone *screens*, which is the daily reality of ticketing.

For your own projects the calculus is the reverse of the operators': dedicated gate
scanners read Aztec, but phone camera apps often do not. Public-facing codes should stay
[QR](/glossary/qr-code): see [QR vs Aztec](/docs/basics/qr-code-vs-aztec) for the full
comparison.

## FAQ

### Is the code on my boarding pass a QR code?
Usually not: mobile boarding passes and rail e-tickets are typically Aztec codes, recognisable by the single square bullseye at the centre rather than three corner squares.

### Can a phone camera scan an Aztec code?
Inconsistently. Some camera apps and libraries support it, many do not. Aztec's home is closed ticketing systems where the operator controls the scanner.

### Why does Aztec not need a quiet zone?
Its finder is a central bullseye rather than edge patterns, so the decoder locks on from the middle outward and never needs contrast at the symbol's boundary.

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