How to Use This Tool
This generator encodes the QR code in your browser, directly from the ISO/IEC 18004 specification. Nothing is uploaded, nothing expires, and there is no redirect in the middle. That last point matters more than it sounds.
The thing to check before using any QR generator
A great many free QR services encode a link to their domain, which then redirects to yours. That gives them analytics, and it gives you a code that stops working the day they shut down or start charging. Printed on a menu, a poster or business cards, that is an expensive failure.
Scan the code you are given with your phone before you print it. If the URL that appears is not exactly the one you typed, the code belongs to someone else. The codes here contain your content and nothing else — you can verify that by scanning the result and reading the URL.
Error correction is not just insurance
Every QR code carries redundant data so it still reads when part of it is dirty, creased or covered. Four levels exist: L recovers about 7% of the code, M 15%, Q 25% and H 30%. Higher correction means less room for your content, so the code grows denser for the same message.
This is also what makes a centre logo possible: the logo destroys modules, and error correction rebuilds them. That only works while the covered area stays within the level's budget.
The rule of thumb: use level H whenever you add a logo, and keep the logo under about 25% of the width. The tool warns you when your combination goes past what the level can rebuild.
Colour, and the mistake everyone makes
Scanners look for contrast, not for black. Any dark-on-light combination works if the contrast is strong enough — and the tool measures it and tells you.
What frequently fails is inverting the code: light modules on a dark background. Some modern phone cameras handle it; a great many dedicated scanners and older phones do not, because the specification assumes light background and dark modules. If a design calls for a dark background, put the code in a light panel rather than inverting it.
The quiet zone is part of the code
The specification requires four modules of blank margin on all four sides. It is not padding for looks — without it the scanner cannot tell where the code ends. Designers crop it constantly, and it is one of the most common causes of a code that mysteriously will not scan. The downloads here include it.
Size on paper
A workable minimum is 2 cm square for a code scanned from about 25 cm away. The rough guide is that scanning distance can be about ten times the code's width. A poster read from three metres needs a code roughly 30 cm across — far larger than most people assume.
Shorter content also helps. A short URL produces fewer modules, so each module is physically larger at the same print size and tolerates more distance and worse light.
What this tool cannot do
It supports versions 1 to 10, which is up to 271 bytes at level L or 119 at level H. That covers any URL, WiFi credentials and a compact vCard. Longer content is refused with a message rather than silently producing something broken. It also has no analytics and no editable short link, because both require a server — if you need to change a destination after printing, you need a redirect service, and you should choose one knowing that the code will depend on it permanently.
