What is a QR Code?
A QR code (Quick Response code) is a two-dimensional barcode invented by Denso Wave in Japan in 1994, originally to track automotive parts during manufacturing. Unlike the familiar one-dimensional barcode (which can only be read horizontally), a QR code stores data in both horizontal and vertical directions — allowing it to hold far more information.
The black squares and white spaces in a QR code represent binary data. The three large square patterns in three corners are called "finder patterns" — they allow QR code readers to detect the code and determine its orientation instantly, regardless of which direction you point your camera.
Modern smartphones can scan QR codes directly from their native camera app without any additional software. iOS 11+ and Android 8+ both include built-in QR code recognition in the camera.
How Much Data Can a QR Code Store?
A QR code can store significantly more data than a standard barcode:
Numeric data: up to 7,089 characters Alphanumeric (letters + numbers): up to 4,296 characters Binary data: up to 2,953 bytes Kanji characters: up to 1,817 characters
QR codes also have built-in error correction — damaged or partially obscured codes can still be read. There are four error correction levels: Level L: recovers up to 7% of damaged data Level M: recovers up to 15% Level Q: recovers up to 25% Level H: recovers up to 30%
Higher error correction levels create more complex QR codes (more data to store) but are more reliable when printing on materials that may get worn or dirty.
What Can a QR Code Contain?
QR codes can encode many types of data beyond simple URLs:
URLs and website links — the most common use. Point scanners directly to a landing page, product page or app download.
Contact information (vCard) — a QR code can store a full digital business card: name, phone, email, organization and website. Scanners offer to add the contact directly to the phone's address book.
WiFi credentials — encode your network name, password and security type. Android and iOS cameras can scan it and automatically join the network without typing the password.
Plain text — any message or note up to the character limit.
Email — pre-fill a recipient, subject and body so scanning opens a ready-to-send email.
SMS — pre-fill a phone number and message text.
Calendar events — include event title, date, time, location and description.
Payment links — many payment platforms support QR codes pointing to payment pages.
QR Codes in Business and Marketing
The practical applications for businesses are extensive:
Restaurant menus — contactless menus became standard during the pandemic and most restaurants have kept them. A QR code links to a digital menu that can be updated without reprinting physical copies.
Product packaging — link to setup guides, video tutorials, warranty registration or additional product information that cannot fit on the label.
Business cards — a QR code on your business card links to your LinkedIn profile, website or portfolio, giving recipients one-tap access to your full professional presence.
Event check-in — QR codes on tickets enable fast, contactless entry verification at events and conferences.
Retail and payments — store QR codes linked to Google Pay, PhonePe or UPI payment addresses let customers pay instantly without handling cash.
Marketing campaigns — physical ads (posters, newspapers, packaging) can link to digital content, promotional pages or app downloads. QR codes bridge offline advertising with online engagement.
How to Create a QR Code
Creating a QR code is straightforward with the right tool:
- 1Decide what the QR code should contain — a URL, text, contact information or WiFi credentials.
- 1Use a QR code generator — enter your content and the tool instantly generates the code as an image.
- 1Choose the right size — for print materials, use the largest available resolution. A minimum of 2 × 2 cm is needed for reliable scanning at normal distances.
- 1Test before printing — scan your generated QR code with multiple devices (Android and iOS) before printing or publishing it. Check that it opens the correct destination.
- 1Download as PNG — for most uses, a PNG file is ideal. For print design, vector SVG formats are better.
- 1Place it prominently — QR codes work best with clear surrounding space (the "quiet zone") and good contrast between the dark and light areas. Avoid placing them on patterned backgrounds.
Static QR codes (where the destination is encoded directly) are permanent and free to generate. Dynamic QR codes (which redirect through a tracking service) allow changing the destination but require a subscription service.