What is a QR code?
Updated 25 July 2026
A QR code is a square, scannable barcode that a phone camera can read in an instant. “QR” stands for “Quick Response” — the format was designed to be decoded very quickly. Point your camera at one and it can open a website, show a menu, share contact details, connect to Wi‑Fi, or display a short message.
Unlike the striped barcodes on supermarket products, a QR code stores information both horizontally and vertically. That two‑dimensional layout lets it hold far more data — and it can still be read from many angles, even if part of it is dirty or damaged.
How does a QR code work?
The pattern of black and white squares (called modules) encodes data as a series of 1s and 0s. Your phone’s camera detects the three large corner squares — the “finder patterns” — to work out the code’s orientation and size, then reads the modules in between.
Crucially, QR codes include error correction. Extra data is baked in so the code still scans even if up to around 30% of it is obscured — which is exactly why you can place a logo in the middle of a well‑made QR code without breaking it.
What can a QR code contain?
- •A website link (by far the most common use)
- •A restaurant or product menu
- •Contact details (vCard) to save straight to a phone
- •Wi‑Fi network details to join without typing a password
- •App store links, event tickets, payment links and more
Static vs dynamic QR codes
There are two kinds. A static QR code has the destination baked directly into the pattern — change your mind and you must reprint it. A dynamic QR code points to a short link you control, so you can change where it goes at any time without reprinting, and you can measure scans.
For anything you print, put on packaging, or plan to keep using, a dynamic code is almost always the right choice. We explain the trade‑offs in our guide to static vs dynamic QR codes.
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Frequently asked questions
- Do QR codes expire?
- A static QR code never expires on its own — but a “free” dynamic code from some sites can stop working when a trial ends or the provider changes its terms. With Host Dada, your dynamic codes keep working for as long as your subscription is active, with transparent pricing and no surprises.
- Are QR codes free to scan?
- Yes. Scanning a QR code is always free for the person scanning, and no app is needed on modern iPhone and Android cameras.
- Can a QR code hold a logo?
- Yes. Thanks to error correction, a properly generated QR code can carry a centred logo and brand colours and still scan reliably.