QR code generator
A link, arbitrary text or Wi-Fi access in one tap. The code is built in your browser and never sent to a server — which matters when it holds a password.
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Why error correction exists
A QR code scans even when part of it is covered, scratched or stained. That is not magic but mathematics: some modules carry Reed–Solomon check symbols rather than data, and the lost parts are reconstructed from them.
Level L tolerates about seven per cent of damage, M fifteen, Q twenty-five, H thirty. You pay in size: at level H the same text needs noticeably more modules.
In practice: L or M is enough for a screen, Q for a printed sticker, and H when a logo sits on top of the code or it will live outdoors.
Why a code may fail to scan
Printed too small. A module should be at least 0.4 mm, ideally 0.6. Below that a phone camera stops resolving neighbouring dots.
The quiet zone was cropped. The code needs a blank border four modules wide. It is included in the downloaded file and is the usual casualty of full-bleed layouts.
Inversion or a coloured background. Scanners look for dark on light.
Too much text. More data means a denser grid. If a paragraph wants to go in, put a short link instead.
Common cases
Questions
Frequently asked questions
Is a QR code with a Wi-Fi password safe?
About as safe as a note on the fridge: whoever sees the code joins the network. In exchange the password is never dictated aloud and never sits in a chat log. What matters more is that our generator builds the code in your browser and sends it nowhere, while many online services post the contents to their server.
What do the error correction levels mean?
A QR code still scans when part of it is covered or damaged. Level L tolerates about 7 per cent of damage, M 15, Q 25, H 30. The price is size: at level H the same text needs noticeably more modules. L or M is fine on a screen; use Q or H for outdoor stickers or printing over an image.
Why does my code not scan?
Three usual causes. Printed too small: a module should be at least 0.4 mm or the camera cannot resolve them. No quiet zone: the four-module blank border is included in the downloaded file — do not crop it. And low contrast: print black on white, since inversion and coloured backgrounds often break recognition.
SVG or PNG?
SVG for printing: it stays perfectly crisp at any size, and edge sharpness is critical for QR. PNG for messengers and slides where a vector file will not paste. Both carry the same code.
Is there a length limit?
Up to code version twenty here — about 850 bytes at the lowest correction level. In practice long texts are a bad idea: the code becomes dense and hard to scan, so a short link works better.
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