What is a QR code?
A QR code (short for Quick Response code) is a square, two-dimensional barcode that stores information in a grid of black and white squares called modules. A phone camera reads the pattern and turns it back into the original data, most often a website link, but also Wi-Fi details, contact cards, payment information, and plain text. QR codes were invented by the Japanese company DENSO WAVE in 1994, and they hold far more data than a one-dimensional barcode because they encode in two directions at once.
How a QR code works
Every QR code is built from fixed patterns that help a scanner find and read it, plus the data area that carries your content and its error correction.
Finder patterns
The three large squares in the corners let a scanner lock onto the code and read it from any angle.
Alignment and timing
Smaller alignment squares and the dotted timing rows keep the grid straight so each module is read in the right place.
Quiet zone
The empty margin around the code (the dashed border) separates it from other graphics so the scanner is not confused.
Data and error correction
The remaining modules hold your content plus extra recovery data, so the code still reads even if part of it is dirty or covered.
What you can put in a QR code
This creator builds each common QR type from simple fields, then encodes them in the exact format scanners expect.
| Type | What it stores | When scanned |
|---|---|---|
| Link | A website address | Opens the page in the browser |
| Text | Any plain text | Shows the text on screen |
| Wi-Fi | Network name, password, security | Offers to join the network |
| Address, subject, message | Opens a pre-filled email | |
| Phone | A phone number | Starts a call to the number |
| SMS | Number and a message | Opens a pre-filled text message |
| Contact | Name, phone, email, company (vCard) | Offers to save a contact |
Error-correction levels explained
QR codes store backup data so they still scan when damaged. A higher level recovers more, but uses more modules, which makes the code denser for the same content. Level M is a good default; use H if you add a logo or expect wear.
| Level | Recovers | Good for |
|---|---|---|
| L (Low) | ~7% | Clean digital use, max data |
| M (Medium) | ~15% | Most everyday codes |
| Q (Quartile) | ~25% | Print that may scuff |
| H (High) | ~30% | Logos, stickers, harsh use |
QR code data capacity
Capacity depends on what you encode and the version (grid size) of the code. The maximums below are for the largest code, version 40, at the lowest error correction. Shorter content keeps your code smaller and easier to scan.
| Encoding mode | Holds | Max characters | Example |
|---|---|---|---|
| Numeric | Digits 0 to 9 | 7,089 | Long reference numbers |
| Alphanumeric | Digits, A to Z, a few symbols | 4,296 | Short codes, plate-style IDs |
| Byte / binary | Any text, including URLs | 2,953 | Website links, Wi-Fi, vCard |
| Kanji | Japanese characters | 1,817 | Japanese text |
Grid size runs from version 1 (21 by 21 modules) up to version 40 (177 by 177 modules), growing by 4 modules per version. The creator above picks the smallest version that fits your content automatically.
Static versus dynamic QR codes
This tool makes static codes, where the data lives in the pattern itself. Dynamic codes store a short redirect link that points somewhere you can change later, which needs a hosting service.
| Feature | Static (this tool) | Dynamic |
|---|---|---|
| Where data lives | Inside the code itself | Behind a short redirect link |
| Editable after printing | No, content is fixed | Yes, change the destination |
| Scan tracking | None | Counts and analytics |
| Needs an account or service | No | Yes, usually a subscription |
| Works forever offline | Yes | Only while the service runs |
| Best for | Fixed links, Wi-Fi, contacts | Campaigns you will update |
How to make a QR code
Pick a content type
Choose Link, Wi-Fi, Email, Phone, SMS, Text, or Contact at the top of the creator.
Fill in your details
Type the link or fields. The preview updates instantly as you go.
Customise the look
Set the colours, module style, and error-correction level. Keep strong contrast so it scans.
Test the scan
Point your phone camera at the preview to confirm it opens what you expect.
Download and use
Save an SVG for print or a high-resolution PNG for screens, then place it where people can reach it.
Best practices for codes that scan
Keep the quiet zone
Leave a clear margin of at least four modules around the code so nothing crowds it.
Use strong contrast
A dark code on a light background scans best. Avoid pale colours or inverting the two.
Size for the distance
Bigger is better. A rough guide is a width of about one tenth of the scanning distance.
Test before you print
Scan with more than one phone, and always proof a printed sample at final size.
Use SVG for print
Vector files stay sharp at any size, so use SVG for posters and packaging.
Raise correction for logos
If you add a logo over the centre, use level H so the extra recovery data keeps it readable.
QR code terms, defined
- Module
- A single black or white square in the grid. The pattern of modules is what a scanner reads.
- Finder pattern
- The three large nested squares in the corners that let a scanner locate and orient the code.
- Quiet zone
- The blank margin around the code, at least four modules wide, that keeps it readable.
- Error correction
- Extra recovery data, set to level L, M, Q, or H, that lets a damaged code still scan.
- Version
- The grid size, from 1 (21 by 21 modules) to 40 (177 by 177). Larger versions hold more data.
- Byte mode
- The encoding used for general text such as URLs and Wi-Fi, with UTF-8 for accents and symbols.
- Static code
- A code whose data is fixed inside the pattern. It never expires and needs no service.
- vCard
- A standard contact format. A vCard QR code lets someone save your details in one scan.