# QR code vs Aztec code

> Aztec codes place their finder bullseye in the centre and need no quiet zone, which suits cramped tickets - airline boarding passes under the IATA BCBP standard and many rail tickets use Aztec. QR codes need a four-module margin but hold more data and are read natively by every phone camera.

Source: https://useqr.app/docs/basics/qr-code-vs-aztec · Last reviewed 2026-08-21 · UseQR is free forever, MIT licensed, no signup.

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## The comparison

| | QR code | Aztec code |
|---|---|---|
| Standard | ISO/IEC 18004 | ISO/IEC 24778 |
| Origin | Denso, Japan, 1994 | Welch Allyn, USA, 1995 |
| Finder | Three corner squares | Single bullseye, dead centre |
| Quiet zone | **4 modules every side** | **None required** |
| Sizes | 21 × 21 to 177 × 177 | 15 × 15 to 151 × 151 |
| Max capacity | 7,089 numeric / 2,953 bytes | 3,832 numeric / 1,914 bytes |
| Error correction | Four levels: 7 / 15 / 25 / 30% | Tunable, roughly 5–95% |
| Orientation | Any angle | Any angle |
| Phone camera support | Universal, native | Inconsistent on stock cameras |

## Aztec's party trick: no quiet zone

A QR code demands a blank margin of at least four modules on every side — miss it and
detection fails, a failure common enough to have
[its own troubleshooting page](/docs/troubleshooting/qr-code-quiet-zone-too-small). Aztec
needs none, because its bullseye finder sits in the middle of the symbol and the decoder
reads outward from it, never touching the edges.

On a boarding pass or thermal-printed rail ticket — narrow paper, dense text, every
millimetre contested — that margin is real estate. It is a large part of why the transport
industry adopted Aztec: the IATA **Bar-Coded Boarding Pass (BCBP)** standard specifies
Aztec, QR and Data Matrix for mobile passes, and Aztec became the common choice for
airline apps. Many European rail operators, Deutsche Bahn among them, print Aztec on
tickets for the same reason.

Aztec's error correction is also unusually flexible: rather than QR's
[four fixed levels](/docs/spec/error-correction-levels-explained), the generator chooses
almost any redundancy percentage, letting ticket systems tune robustness precisely.

## Where QR wins

**Readers.** The infrastructure scanning boarding passes — airport gates, train conductors'
devices — is purpose-built and reads Aztec happily. Stock phone cameras are another matter:
QR is the only 2D symbology you can rely on a random consumer's camera app to recognise.
Publish an Aztec code on a poster and most of your audience will point, wait, and give up.

**Capacity and ecosystem.** QR holds substantially more data at the top end, supports
[structured append](/glossary/structured-append) and [kanji mode](/glossary/kanji-mode),
and carries the world's payment, WiFi and contact-card conventions. Every generator,
including [UseQR's](/url-qr-code), and every decode pipeline is built around it.

## Which to use

- **You operate both ends** (issue tickets *and* control the scanners) → Aztec is a fine,
  compact choice, and the aviation and rail standards may require it.
- **The public scans with their own phones** → QR code, always.
- **Space is tight but readers are yours** → Aztec's zero quiet zone or Data Matrix's
  one-module margin both beat QR's four — the
  [quiet zone requirements](/docs/spec/quiet-zone-requirements) page has the geometry.

## FAQ

### What is the difference between an Aztec code and a QR code?
An Aztec code has a single bullseye finder at its centre and requires no quiet zone, while a QR code has three corner finder squares and needs a four-module blank margin. They are separate ISO standards with incompatible decoders.

### Why do boarding passes use Aztec codes?
The IATA BCBP standard permits Aztec, QR and Data Matrix, and Aztec's lack of a quiet zone plus centre-out decoding suits small screens and cramped thermal prints. Airport scanners are built to read all the permitted formats.

### Can a phone scan an Aztec code?
Dedicated apps and Google Lens generally can, but stock camera apps are inconsistent about Aztec. For anything the general public scans with their own phone, a QR code is the reliable choice.

### Does an Aztec code hold more than a QR code?
No. Aztec tops out around 3,832 digits or 1,914 bytes, against QR's 7,089 digits or 2,953 bytes. Aztec's advantage is compactness in constrained print, not capacity.

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