How to create a QR code
- Choose the content type: a URL or plain text, Wi-Fi login details, an email or a phone number.
- Fill in the fields. The preview updates as you type.
- Adjust the colours, size and error-correction level if needed.
- Scan the preview with your phone camera to check it opens what you expect.
- Download the code as PNG for screens or SVG for print.
How QR codes store data
A QR code (Quick Response code) is a two-dimensional barcode defined in the ISO/IEC 18004 standard. The three large squares in the corners let a scanner find the code and work out its orientation, and the remaining modules encode your data along with Reed-Solomon error-correction data. That redundancy is why a code can still be read when part of it is damaged: level L can recover roughly 7% of the codewords, M about 15%, Q about 25% and H about 30%.
Special content types are just text in an agreed format that phone cameras recognise. A Wi-Fi code contains a string such as WIFI:T:WPA;S:MyNetwork;P:secret;;, where special characters like semicolons are escaped with a backslash. Email codes use a mailto: link and phone codes a tel: link.
Tips for codes that scan reliably
- Keep content short. More characters means more modules, so a long URL produces a dense code that is harder to scan from a distance. Remove tracking parameters you do not need.
- Use strong contrast. A dark foreground on a light background works with the widest range of scanner apps.
- Leave the quiet zone. The blank margin around the code is part of the standard; do not crop it off in your design.
- Size for the distance. A code on a poster read from across a room needs to be much larger than one on a business card. Test at the real viewing distance before printing.
- Include the country code for phone numbers, so the number works for international visitors.