# QR code

> A QR code (Quick Response code) is a two-dimensional matrix barcode invented at Denso Wave in 1994 and standardised as ISO/IEC 18004. It stores data as a grid of dark and light modules, readable from any orientation, holding up to 7,089 digits or 2,953 bytes with built-in error correction.

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

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## The parts, at a glance

Every QR code is a square grid of [modules](/glossary/module), from 21 × 21 at
[version](/glossary/version) 1 to 177 × 177 at version 40. Three corner
[finder patterns](/glossary/finder-pattern) let a scanner locate and orient the symbol from
any angle, [timing patterns](/glossary/timing-pattern) calibrate the grid,
[alignment patterns](/glossary/alignment-pattern) correct perspective, and a
[quiet zone](/glossary/quiet-zone) of clear space frames it all. The data itself is protected
by [Reed–Solomon](/glossary/reed-solomon) redundancy at one of four
[error correction levels](/glossary/error-correction-level), so up to 30% of the pattern can
be damaged and still decode.

"QR" is short for *Quick Response*: Masahiro Hara's team at Denso Wave built it in 1994 to
track car parts faster than linear barcodes allowed. Denso Wave holds patents but has
[never exercised them](/docs/basics/are-qr-codes-patented-and-free-to-use) against
standard-conforming use, which (together with the open ISO/IEC 18004 specification) is why
anyone can generate and read QR codes without paying or asking.

## What a QR code contains

Nothing but data. A [payload](/glossary/payload) (a URL, WiFi credentials, a vCard, a
payment string) is encoded once, at generation time. A
[static code](/glossary/static-qr-code) never changes and never expires; a
[dynamic code](/glossary/dynamic-qr-code) stores a redirect URL owned by a service instead.
Smaller and rectangular relatives exist for tight spaces:
[Micro QR](/glossary/micro-qr) and [rMQR](/glossary/rmqr).

## FAQ

### What does QR stand for?
Quick Response. The name refers to decode speed, the design goal at Denso Wave in 1994 was a code that scanners could locate and read faster than the stacked barcodes of the time.

### How much data fits in a QR code?
Up to 7,089 digits, 4,296 alphanumeric characters or 2,953 bytes at the largest size with the lowest error correction. Practical codes stay far smaller, a URL of under 100 characters scans best.

### Are QR codes free to use?
Yes. The specification is an open ISO standard, Denso Wave permits standard use of its patents, and the "QR Code" trademark only restricts using the name for other products, not making or scanning codes.

## Try it

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