QR codes explained: how they work and where to use them

QR codes went from niche tech to everyday infrastructure during the pandemic — and they are not going away. Here is what is inside one and how to use them well.

What is a QR code?

A QR (Quick Response) code is a 2-dimensional barcode that can store text, URLs, contact details, Wi-Fi credentials and more. The black-and-white squares encode data and the three corner markers help cameras find the code at any angle.

What you can put in a QR code

• A URL — by far the most common use.
• Plain text, up to a few thousand characters.
• Contact card (vCard) data.
• Wi-Fi network name and password.
• Calendar events.

Best practices

Keep it short

Shorter content means a less dense code that scans more reliably.

Pick the right error correction level

QR codes have four levels — L, M, Q, H — that let the code stay readable even if part of it is damaged. Use M for most uses; use H if the code will be printed on packaging or stickers that may scuff.

Test before you print

Always scan the final design with multiple phones in low light before sending it to print.

Privacy

Many free QR generators store the data you encode on their servers or wrap your URL in a redirect to track scans. Our QR Code Generator builds the image directly in your browser — nothing is uploaded.

Ideas for everyday use

• Print a Wi-Fi QR code for guests at your home or short-term rental.
• Add a QR code to a business card linking to your portfolio.
• Stick a QR code on packaging that opens your product manual.