QR Codes Explained: How They Work and How to Make One
QR codes — those square patterns of black and white dots — went from novelty to everyday essential. They appear on menus, posters, payment screens, packaging and business cards because they turn a quick phone-camera scan into an instant action.
How a QR code works
A QR (Quick Response) code is a two-dimensional barcode. Unlike a traditional barcode that stores data in one direction, a QR code stores it both horizontally and vertically, so it can hold far more. Your phone camera reads the pattern and decodes it into text, a link or another instruction. The three large squares in the corners help the scanner find and orient the code.
What QR codes can store
- Website links — by far the most common use.
- Plain text or contact details (so a scan can save a phone number).
- Wi-Fi network details, so guests can join without typing a password.
- Payment information for quick transfers.
- Event details, app download links and more.
Built-in error correction
QR codes include error correction, which is why they still scan when slightly dirty, creased or partly covered — even with a logo placed in the middle. Higher error-correction levels let the code survive more damage but make the pattern denser. For most uses, a medium level is a good balance.
Tips for QR codes that actually get scanned
- Keep enough quiet space (a margin) around the code.
- Make it large enough to scan from the expected distance — a poster needs a bigger code than a business card.
- Maintain strong contrast; dark code on a light background works best.
- Always test the code with a real phone before printing.
Static vs dynamic QR codes
Not all QR codes are equal, and the difference matters. A static code has the destination baked straight into the pattern — simple, free, and it works forever, but if the link changes you have to print a brand-new code. A dynamic code instead points to a short redirect you can re-aim whenever you like, so the same printed code can lead somewhere new next month, and you can see how many times it was scanned. For a flyer you'll print once, static is perfect. For packaging, signage or a campaign you might update, dynamic earns its keep.
The security side people overlook
Because a QR code hides its destination behind a pattern, you can't tell where it leads just by looking — and scammers have noticed. 'Quishing' attacks stick fake codes over real ones on parking meters, posters and restaurant tables to send you to phishing pages. The habit worth building: after scanning, glance at the URL your phone previews before you tap it, and be wary of any code that immediately asks you to log in or pay. As the person making codes, you earn trust by keeping yours on a clear, expected web address.
Frequently asked questions
Do QR codes expire?
A static code never expires — the data lives in the pattern itself. A dynamic code keeps working as long as the redirect service behind it stays active, so that one depends on the provider.
Can I put a logo in the middle of a QR code?
Yes. The built-in error correction lets a code still scan with a logo or small graphic over the centre. Just don't cover too much of it, and test on a real phone before printing.
Why won't my QR code scan?
Usually it's too small, too low-contrast, or missing the quiet margin around it. Make it bigger, use dark-on-light with strong contrast, leave clear space at the edges, and test it from the distance people will actually stand.
The bottom line
QR codes are a simple bridge from the physical world to a digital action, robust enough to survive real-world wear. Make one for a link, your Wi-Fi or your contact details in seconds with our free generator.