What Is a QR Code?
A QR (Quick Response) code is a two-dimensional barcode that stores data — a link, WiFi login, contact card and more — in a square grid of black and white modules. A phone camera reads it instantly and acts on the content, such as opening a website. QR codes hold far more data than a traditional one-dimensional barcode.
QR codes are everywhere — on menus, packaging, posters and payment terminals — but what actually are they? This page explains what a QR code is, how it works, what it can store, and the main types you'll encounter. When you're ready to make one, every code type below links to a dedicated free generator.
How It Works
The camera detects the pattern
Three large corner squares let the scanner find and orient the code from any angle.
The modules are decoded
The grid of black and white squares (modules) is read as binary data, with error correction fixing damage.
The phone acts on the content
The decoded data — a link, WiFi login, contact — triggers the matching action on the phone.
How QR codes work
A QR code stores data in a grid of small squares called modules. The three large squares in the corners are finder patterns that let a scanner locate and orient the code, so it reads correctly at any angle. Built-in error correction adds redundancy, allowing the code to be decoded even if part of it is dirty, damaged or covered by a logo. A phone camera captures the pattern, decodes the binary data, and performs the encoded action.
What a QR code can store
QR codes are versatile. The most common is a website link, but they can also store WiFi credentials, a full contact card (vCard), an email or SMS draft, a phone number, a calendar event, a map location, or plain text. Because a QR code is two-dimensional, it holds far more data than a traditional barcode — up to several thousand characters depending on the version and error-correction level.
QR codes vs barcodes
A traditional barcode is one-dimensional — a row of lines read left to right — and stores only a small number, like a product ID. A QR code is two-dimensional, storing data both horizontally and vertically, which massively increases capacity and lets it hold real content like URLs and contact details. QR codes are also readable from any orientation and tolerate damage thanks to error correction.
Common types of QR code
What each type stores and a typical use. Each links to a free generator below.
| Type | What it stores | Common use |
|---|---|---|
| URL | A web link | Posters, packaging, menus |
| WiFi | Network name + password | Cafes, offices, rentals |
| vCard | Contact details | Business cards, email signatures |
| A pre-filled email | Support, feedback, contact | |
| Location | A map point | Storefronts, events, signs |
| Calendar | An event | Invitations, tickets, posters |
Frequently Asked Questions
What does QR stand for?
QR stands for 'Quick Response'. The codes were designed to be read quickly, storing far more data than a standard barcode.
Are QR codes free to create and use?
Static QR codes are free to make and use, including commercially. QR Gen creates them free with no signup or watermark.
Do QR codes expire?
Static QR codes do not expire — they keep working as long as their content (such as a link) stays valid. Only dynamic codes that rely on a redirect service can stop working.