What Is a QR Code and How Do You Create One?
QR codes went from novelty to everywhere. Here is what is actually inside that square of dots — and how to make one that scans every time.
By ToolJolt Team · May 20, 2026
How a QR code works
A QR (Quick Response) code is a 2D barcode that stores data in a grid of black and white squares. Cameras read it in any orientation thanks to the three large 'finder' squares in the corners. It can hold far more than a traditional barcode — URLs, text, contact cards, Wi-Fi credentials and more.
What you can put in one
- A website link (by far the most common use).
- Plain text or a phone number.
- Wi-Fi network details so guests connect with one scan.
- A contact card (vCard) that saves straight to a phone.
Error correction is built in
QR codes include redundancy, so they still scan even if part is dirty, damaged or covered by a small logo. Higher error-correction levels survive more damage but make the code denser — a useful trade-off when you want to brand the centre.
Make codes that scan reliably
- Keep strong contrast — dark code on a light background.
- Leave a 'quiet zone' (clear margin) around the code.
- Do not shrink it too far; for print, bigger is safer.
- Test it with a couple of real phones before you publish.
Generate one free
ToolJolt's QR code generator runs in your browser and lets you create and download a code instantly — no sign-up, no watermark.
Free tools mentioned in this guide
Frequently asked questions
Do QR codes expire?
A static QR code (with the data baked in, like a plain URL) never expires. Only 'dynamic' codes that redirect through a third-party service can stop working if that service does.
Can a QR code contain a logo?
Yes — error correction lets a small logo sit in the centre. Keep it small and test the code so it still scans.
Why won't my QR code scan?
Usually low contrast, too small a size, no quiet-zone margin, or too much data crammed in. Increase size and contrast and try again.