RunToolRunQR Code Generator
Generate QR codes.
How to Create a QR Code
Enter your content
Paste a URL, text, phone number or Wi-Fi details.
The code is generated locally
The QR matrix is drawn instantly in your browser as you type.
Download as PNG
Save a high-resolution image ready for print or screen.
What a QR code physically contains
A QR code is a grid of modules encoding a short string of data along with heavy error-correction information and fixed patterns that let a scanner find and orient the code. The three large squares in the corners are position markers; the smaller square is an alignment marker; the rest is data and correction.
Capacity depends on version and error-correction level, and it is smaller than people assume — a few hundred characters in practice for a code that stays comfortably scannable. Long URLs push the code to a higher version with a denser grid, which needs to be printed larger or scanned closer. Shortening a link before encoding it produces a visibly simpler, more reliable code.
Error correction is why codes still work when damaged
Four levels exist, recovering roughly 7, 15, 25 and 30 percent of the code. That redundancy is what allows a code to scan with a coffee ring across it or a logo placed in the middle. Higher correction means more modules for the same data, so the code becomes denser at the same physical size.
The common mistake is choosing maximum correction by default. On a business card printed at two centimetres, the extra density can make the code harder to scan than a lower correction level would have been. Match the level to the risk: high for something printed on a surface that will be handled, damaged or partly covered; low or medium for a clean digital display.
The quiet zone and contrast
A QR code needs a clear margin of at least four modules on every side. Scanners use that empty border to distinguish the code from its surroundings, and codes placed flush against text or a coloured background fail for this reason far more often than for any other. If a code will not scan and looks otherwise fine, the margin is the first thing to check.
Contrast follows the same logic. Dark modules on a light background is what scanners expect; inverting it works on some readers and not others. Coloured codes are possible if the contrast ratio stays high, but a pale code on a mid-tone background is a code that works on your phone in good light and fails on a customer's phone in a restaurant.
Static codes cannot be edited
The URL is encoded in the pattern itself. Once a code is printed, changing where it points is impossible — the destination is the code. Printing ten thousand flyers pointing at a page you later move means ten thousand dead codes.
The standard defence is to encode a link you control and can redirect: your own short domain, or a page whose content you can change. That way the code stays valid permanently and the destination becomes a decision you can revisit. Anything printed at volume should point at something you own rather than at a third-party URL that may not outlive the campaign.
Testing before printing
Test with more than one phone, in the light the code will actually live in, at the size it will actually be printed. A code that scans instantly on a bright screen at arm's length can fail on a menu in a dim room, and the difference is usually size: as a rule of thumb, a code should be about a tenth of the distance it is scanned from.
Generation happens entirely in your browser, so codes containing private URLs, internal addresses or contact details are not sent anywhere. Nothing here logs what you encode or counts scans — a plain code with no tracking layer in the middle.