A QR code is a two-dimensional barcode that stores data in a square grid of dark and light modules. A phone camera or scanner reads the grid and turns it into a URL, text, contact card, Wi-Fi login, payment instruction, or another small payload.
QR stands for Quick Response. The format was created by Denso Wave in 1994 for tracking parts, but it became common on phones because a camera can recognize the code from different angles.
If you already know the destination you want to encode, make one with the QR Code Generator and test it on the device people will use to scan it.
QR code vs barcode
A one-dimensional barcode stores information along a line. A QR code stores information across width and height.
| Code type | Shape | Common payload |
|---|---|---|
| Barcode | vertical lines | product number or inventory ID |
| QR code | square grid | URL, text, contact, Wi-Fi, payment data |
That second dimension gives QR codes more capacity and makes them easier to scan from printed surfaces, screens, packaging, and signs.
The visible parts
A QR code is not random noise. The grid contains functional patterns and data areas.
- Finder patterns: the three large corner squares that help the scanner locate and rotate the code.
- Timing patterns: alternating dark and light modules that define grid spacing.
- Alignment patterns: smaller squares that help with distortion on larger codes.
- Format information: metadata for error correction and masking.
- Data modules: the encoded payload and correction data.
The scanner first finds the corner patterns, maps the grid, samples each module, repairs errors if needed, then decodes the payload.
What QR codes can store
A QR code can store several kinds of structured data:
| Payload | Result after scanning |
|---|---|
| URL | opens a web page |
| plain text | displays the text |
| Wi-Fi credentials | offers to join a network |
| vCard | saves a contact |
mailto: link | drafts an email |
tel: link | starts a phone call |
| map URL | opens a location |
| payment payload | opens a compatible banking flow |
The more data you encode, the denser the grid becomes. Dense QR codes need more print size, more contrast, and a better quiet zone around the outside.
Static and dynamic QR codes
A static QR code contains the final payload directly. If it encodes https://example.com/menu, that exact URL is inside the grid. Once printed, the destination cannot change unless the URL itself redirects somewhere else.
A dynamic QR code usually stores a short redirect URL controlled by a service. The service can change the final destination later and collect scan analytics.
Static codes are better when you want the code to keep working without a third-party redirect service. Dynamic codes are better when campaign destinations may change after printing.
Error correction
QR codes include redundant data so a scanner can recover from damage, blur, glare, or a small logo in the center.
| Level | Approximate recovery | Tradeoff |
|---|---|---|
| L | 7% | lower density |
| M | 15% | common default |
| Q | 25% | safer for print and logos |
| H | 30% | highest redundancy, denser grid |
Higher error correction improves damage tolerance, but it also adds modules. A denser QR code may need to be printed larger.
Print limits
A QR code that scans on a monitor can fail on paper. Print introduces ink spread, glare, folds, distance, and low light.
Before printing a large batch:
- keep strong contrast between foreground and background
- leave a quiet zone around the code
- avoid placing important design elements over finder patterns
- test at the final physical size
- scan with more than one phone model
A centered logo can work, but only when error correction, contrast, and size leave enough readable modules.
Make the destination trustworthy
People decide whether to scan based on context. Put the QR code near a clear label such as Menu, Join Wi-Fi, Download guide, or Leave a review.
For public signs and packaging, use a visible domain people recognize. A QR code that hides the destination behind an unfamiliar short link may scan less often, even when the code itself is valid.
QR codes work best when the scan leads to one specific action. Encode the shortest destination that still gives people enough confidence to scan.
