What Is a QR Code and How Does It Work?

QR codes appear on restaurant tables, product packaging, event tickets, business cards, and bus stops. Most people scan them without thinking twice — but very few know how they actually store and transmit information. This guide explains the technology behind QR codes, what they can hold, and when they're the right tool for the job.

What QR stands for

QR stands for Quick Response. The format was invented in 1994 by Denso Wave, a Toyota subsidiary, to track vehicle parts during manufacturing. The "quick response" referred to the fast scanning speed — QR codes can be decoded almost instantly, unlike barcodes which require a precise scan angle and closer positioning.

The patent holder made the format freely available without licensing fees, which is a key reason QR codes became a universal standard rather than a proprietary format owned by one company.

How QR codes store information

A QR code is a two-dimensional matrix barcode — a square grid of black and white modules (small squares) arranged in a pattern. Unlike a traditional barcode, which only encodes data in one dimension (horizontal), a QR code encodes data in two dimensions (horizontal and vertical), which is why it can store far more information.

The data is encoded using a combination of numeric, alphanumeric, binary, and kanji encoding modes depending on the content. A QR code encoding a simple URL uses less space than one encoding arbitrary binary data.

The anatomy of a QR code

Every QR code contains several functional regions:

Finder patterns — The three identical square patterns in three corners of the code. These tell the scanner the orientation and boundaries of the code. They're why QR codes can be scanned from any angle and even upside down.

Alignment patterns — Smaller squares inside larger QR codes that help scanners compensate for image distortion (such as when the code is printed on a curved surface).

Timing patterns — Alternating black and white modules that run between the finder patterns. These establish the grid spacing so the scanner knows the size of each module.

Format information — Strips adjacent to the finder patterns that encode the error correction level and mask pattern being used.

Data and error correction area — The remaining modules store the actual content plus error correction data.

Error correction

One of the most important features of QR codes is built-in error correction. QR codes use Reed-Solomon error correction, which allows them to be read even when part of the code is damaged, obscured, or dirty.

There are four error correction levels:

Higher error correction levels produce denser, more complex QR codes because more of the code's space is used for redundancy rather than data. This is why QR codes used in logos — where part of the pattern may be covered by the logo itself — are generated with High (H) error correction.

What a QR code can contain

QR codes store text. What makes them versatile is how that text is interpreted by the scanning device:

URLs — The most common use. Scanning opens a website in the device's browser.

Plain text — Any text up to the character limit.

Email addresses — Using the mailto: format, a QR code can pre-populate an email to a specific address.

Phone numbers — Using the tel: format, scanning prompts the user to call a number.

SMS messages — Using smsto:, scanning opens a pre-populated SMS to a phone number.

Wi-Fi credentials — A standardized format encodes the network name (SSID), password, and security type.

vCard contacts — A QR code can encode a full contact card.

Geographic coordinates — A QR code can encode GPS coordinates that open in the device's map application.

Payment information — Many payment systems (PayNow, GCash, Maya, WeChat Pay, Alipay) use QR codes to encode payment routing information.

Capacity limits

QR code capacity depends on the encoding mode and error correction level. At the maximum (version 40, Low error correction):

• •Numeric only: up to 7,089 characters
• •Alphanumeric: up to 4,296 characters
• •Binary/byte: up to 2,953 bytes

In practice, most QR codes used for URLs contain 20–80 characters. Longer content produces denser, harder-to-scan codes.

Why QR codes became mainstream

QR codes existed for over two decades before becoming widely adopted by consumers. The shift happened for two reasons:

Smartphones added QR scanning to the default camera app. For years, scanning required downloading a separate app — a significant friction point. Once iOS and Android cameras could scan QR codes natively, usage exploded.

The COVID-19 pandemic accelerated contactless adoption. Restaurants replaced physical menus with QR code menus overnight. The pandemic compressed years of QR adoption into months.

Generating your own QR codes

BG Bueno's free QR Code Generator lets you create QR codes for any text or URL directly in your browser — no account, no upload, no watermark. Choose your size, color scheme, and download as PNG or SVG.

SVG format is ideal for QR codes used in print — it scales to any size without pixelation. PNG is suitable for digital use, presentations, and screen display.