What Is a QR Code and How Do You Make One?

What a QR code is

A QR (Quick Response) code is a two-dimensional barcode: a grid of black and white squares that encodes data both horizontally and vertically, so it holds far more than an old-style striped barcode. A phone camera reads the pattern and acts on whatever it contains — usually opening a link.

What you can put in one

A QR code can carry a web address, plain text, contact details (vCard), WiFi credentials, an email or phone number, or payment information. The most common by far is a URL, which is why scanning one usually opens a page. The QR Code Generator here creates them in your browser from any of these.

Error correction

QR codes are built with redundancy, so they still scan when part of the code is dirty, crumpled or covered — up to around 30% at the highest level. That is how brands can drop a logo in the middle of a code and still have it work. Higher error correction adds resilience but makes the pattern denser.

Making one that reliably scans

Keep it simple: a shorter URL makes a less dense, easier-to-scan code, so shorten long links first. Keep strong contrast (dark code on a light background, not the reverse), leave a quiet margin of blank space around it, and print it large enough for the scanning distance — a poster code must be bigger than a business-card one. Always test it with a real phone before printing.

Frequently asked questions

Do QR codes expire? The code itself does not, but the link it points to can go dead — a dynamic redirect link lets you change the destination without reprinting.

Can a QR code contain a virus? Not by itself — it just carries data, usually a link; the risk is where that link leads, so treat unknown codes like unknown links.

Why will not my code scan? Usually low contrast, too little margin, too much data, or it is printed too small.