QR code glossary

Short for Quick Response Code. A two-dimensional matrix barcode that encodes data — most commonly a URL — as a pattern of dark modules on a light background. Any modern smartphone camera can decode it without a separate app.

A QR code that permanently encodes its destination or content. The data is embedded directly in the code pattern itself. Static QR codes cannot be edited after creation, have no expiry date, and do not require a server to function — they work offline forever.

A QR code that encodes a short redirect URL managed by a server. The final destination can be changed at any time without reprinting the code. Dynamic QR codes enable scan analytics (device type, location, date/time) and are essential for editable print campaigns.

A single data cell in the QR code grid — the smallest unit of the code pattern. Standard QR codes have square modules. With a custom QR code designer, modules can be styled as circles, pills, rounded squares, or other shapes without affecting scannability.

The three identical square markers positioned in the top-left, top-right, and bottom-left corners of every QR code. Scanners locate these first to determine the code's position, size, and rotation angle before decoding the data.

A smaller square marker embedded in larger QR codes (version 2 and above) to help scanners correct for image distortion caused by curved or photographed surfaces. The number of alignment patterns increases with QR code version.

Alternating dark and light modules forming horizontal and vertical lines between the finder patterns. They establish the coordinate grid that allows the scanner to determine the size of each module.

The mandatory white border surrounding the entire QR code. The minimum quiet zone width is four modules. Without a sufficient quiet zone, scanners struggle to distinguish the code boundary from surrounding content — a common cause of scan failure on printed materials.

QR codes are categorised into 40 versions, each defining the grid size. Version 1 is 21×21 modules and stores up to 17 numeric characters. Version 40 is 177×177 modules and stores up to 7,089 numeric characters. Higher data capacity requires higher version.

The maximum amount of data a QR code can store, which depends on version (grid size), error correction level, and data type. URL QR codes typically use 50–150 characters. Higher error correction reduces capacity.

A redundancy mechanism using Reed-Solomon coding that allows a QR code to be read even when partially damaged, obscured, or covered by a logo. There are four levels, each tolerating progressively more damage at the cost of reduced data capacity.

Low error correction. Tolerates up to 7% damage or coverage. Produces the smallest, least dense QR code. Use when the QR code will be printed cleanly at a large size with no logo.

Medium error correction. Tolerates up to 15% damage or coverage. The default level for most QR generators. Balances code density and reliability for typical print use.

Quartile error correction. Tolerates up to 25% damage or coverage. Recommended for QR codes placed in environments prone to physical wear — packaging, stickers, outdoor signage.

High error correction. Tolerates up to 30% damage or coverage. Required when embedding a logo in the centre of a QR code, since the logo obscures that portion of the data. Produces the densest, most complex QR code.

The mathematical algorithm underlying QR code error correction. It adds redundant data that allows the decoder to reconstruct missing or corrupted modules. Developed by Irving Reed and Gustave Solomon at MIT Lincoln Laboratory in 1960.

The visual shape applied to each module in a QR code. Options include square (classic), rounded (soft corners), dots (perfect circles), classy (notched angular), soft (lozenge), and pill (capsule). All styles remain scannable with correct contrast.

The visual shape applied independently to the three corner finder pattern squares and their inner dots. Can be styled separately from the inner module dot style, enabling many unique combinations.

The practice of placing a brand logo in the centre of a QR code. Requires error correction level H (30% tolerance). The logo must not cover more than 30% of the total code area — QR Maker enforces this limit automatically.

The maximum area a logo can occupy inside a QR code while maintaining reliable scannability. At error correction level H, the safe zone is approximately 30% of the total code area. Exceeding this risks scan failure.

The luminance difference between the dark module colour and the light background colour, expressed as a ratio. The minimum safe contrast ratio for QR codes is 3:1 (WCAG AA). A ratio of 4.5:1 or higher is recommended for reliable scanning across all lighting conditions.

Web Content Accessibility Guidelines. QR Maker uses WCAG luminance formula to calculate the contrast ratio between module and background colours and displays a live safety badge (green/yellow/red) before download.

A colour transition applied to QR code modules. Can be linear (horizontal, vertical, diagonal) or radial. QR Maker validates contrast at the lightest gradient point to ensure the full code remains scannable.

A decorative border added around a QR code with custom text — such as "Scan to Order", "Get Directions", or "View Menu". Frames increase scan rates by telling users what they will get before they scan.

The colour of the QR code modules (the dark squares/dots). Must be darker than the background to maintain sufficient contrast. Any brand hex colour can be used as long as the contrast ratio is at least 3:1.

The colour behind the QR code modules. Should be lighter than the foreground colour. Transparent backgrounds are supported in Pro exports and work well when QR codes are placed on coloured substrates.

Scalable Vector Graphics format. QR codes exported as SVG can be scaled to any size without quality loss, making them ideal for large-format print — banners, vehicle wraps, billboards. QR Maker provides SVG export on the free plan.

Raster image format. QR Maker free plan exports PNG at 300px. Pro plan supports up to 4000px and transparent background PNG. PNG is best for digital use — websites, email, presentations.

A one-click combination of dot style, corner style, foreground colour, and background colour. QR Maker includes 10 curated presets (Classic, Rounded, Dots, Classy, Forest, Slate, etc.) that can be further customised.

Data collected each time a dynamic QR code is scanned. Includes total scan count, unique scan count, device type, operating system, browser, country, city, timestamp, and time-of-day. Only available on dynamic QR codes.

The percentage of people who see a QR code and scan it. Influenced by placement visibility, CTA text, code size, and whether the audience has a clear reason to scan. Typical print scan rates: 1–5%. Well-placed codes with strong CTAs can reach 15%+.

A scan from a device that has not previously scanned the same QR code (determined by device fingerprint within a rolling time window). Distinguishes true reach from repeat visitors.

The raw count of all scan events recorded for a QR code, including repeat scans from the same device. Measures engagement volume rather than unique reach.

Query string tags appended to a destination URL to attribute traffic sources in Google Analytics. The five parameters are: utm_source (traffic source), utm_medium (channel), utm_campaign (campaign name), utm_content (ad variation), and utm_term (keyword).

Google's web analytics platform. QR code scans can be tracked in GA4 by appending UTM parameters to the QR destination URL. GA4 records each scan as a session attributed to the campaign, source, and medium.

The practice of adding UTM parameters to each QR code destination URL to identify which physical placement, campaign, or channel generated each scan in Google Analytics.

The short URL embedded in a dynamic QR code. When scanned, the redirect server logs the scan metadata and immediately forwards the user to the final destination URL. The redirect is invisible and takes less than 300ms.

The process of estimating a scanner's physical location from their IP address. Used in QR code analytics to attribute scans to a country, US state, or city. Accurate to city level in most cases; not suitable for street-level location.

Download of scan analytics data as a comma-separated values file. Available in QR Maker Pro. Each row contains a scan event with timestamp, device, OS, country, and city.

An analytics visualisation showing which hours of the day receive the most scans. Helps optimise the timing of email campaigns, social posts, and physical placements that feature QR codes.

A QR code that encodes a web address (URL). The most common QR code type. When scanned, the device opens the URL in the default browser. Supports any valid URL including https, http, and deep links.

A QR code that encodes Wi-Fi network credentials (SSID, password, and security type). When scanned, the device prompts the user to join the network — no manual password typing required.

A QR code that encodes contact information (name, phone, email, address, website) in vCard format. When scanned, the device opens a prompt to save the contact to the address book.

A compact contact card QR code format, similar to vCard but with a smaller data footprint. Natively supported on many Asian smartphones and widely compatible with iOS and Android.

A QR code encoding an iCalendar (iCal) event with title, start time, end time, location, and description. When scanned, the device opens the calendar app and pre-fills the event details.

A QR code linking to a hosted PDF file. Used for menus, catalogues, instruction manuals, and brochures. The PDF must be accessible via a public URL; the QR code encodes that URL.

A QR code encoding geographic coordinates or a Google Maps URL. When scanned, the device opens the maps application with navigation pre-set to that location.

A QR code that, when scanned, opens the device's messaging app with a pre-filled recipient number and/or message body. Commonly used for opt-in campaigns and customer service.

A QR code that opens the device's email client with a pre-filled recipient address, subject line, and/or body text. Used on business cards, signage, and print ads.

A QR code that opens a WhatsApp chat with a specified phone number, optionally pre-filling a message. Used for customer service, sales enquiries, and business communication.

The smallest physical size at which a QR code can be reliably scanned. The recommended minimum is 1.5 × 1.5 inches (3.8 × 3.8 cm) for scanning at arm's length. At smaller sizes, use a low-complexity QR code with a short URL and level L error correction.

Dots per inch — the density of printed ink dots. For QR codes, a minimum of 300 DPI is recommended for print. At 300 DPI, a QR code intended to print at 2 inches should be at least 600×600 pixels. QR Maker Pro exports up to 4000px for large-format print.

The ink spread that occurs during printing, causing dots to print larger than their digital specification. Dot gain reduces the whitespace between QR modules, especially with dot and pill styles at small sizes. Always test a print at actual size before committing to a full print run.

The maximum distance at which a QR code can be scanned reliably. The rule of thumb: the scanning distance equals 10× the minimum dimension of the QR code. A 2-inch code can be scanned from ~20 inches. A 6-inch code can be scanned from ~60 inches (5 feet).