A QR code is a square barcode a phone camera can read. Who invented it, what the squares mean, how damaged codes still scan, and static vs dynamic codes.
A QR code is a square barcode a phone camera can read. The pattern is text, usually a web address, and the phone turns it back into a link you can tap. DENSO WAVE announced it in Japan in 1994, and anyone can use it without a license or fee.
The QR code was developed at DENSO WAVE, then part of the Japanese car parts maker DENSO, by a small team led by Masahiro Hara. DENSO WAVE announced it in 1994. Per the company's history page, the problem was the ordinary barcode: it "can only hold 20 alphanumeric characters or so of information", and factories wanted to encode more, including Japanese characters.
DENSO WAVE kept the patent but declared it would not exercise it, and published the specification so anyone could use it. That's why QR codes are everywhere: no license, no fee. Its FAQ says plainly: "No application is necessary to use a QR Code."
Look at any QR code and you'll see the same parts:
Part of every QR code is spare data. If a corner is smudged, torn or covered by a sticker, the reader rebuilds what's missing. There are four levels of this error correction, L, M, Q and H. DENSO WAVE says level M, which can restore about 15% of the data, is "most frequently selected", and that higher levels suit dirty environments like factories. The trade-off: more correction means more squares for the same content, so the code gets denser.
This is also why a small logo can sit in the middle of some codes. It covers squares the error correction can rebuild.
The phone doesn't need the internet to read the code. It only needs it to open what the code points to. To try it yourself, see how to scan a QR code on iPhone and Android.
Mostly a web address. But the text can also be a contact card that saves straight to the phone, Wi-Fi details, an email or text message ready to send, or plain text. Our free QR code generator makes all of these with no sign-up.
A static QR code holds the destination itself. The address is in the pattern, so it can never change. If the page moves, the printed code is wrong for good.
A dynamic QR code holds a short link instead, like go.qrzy.co/demodirect. The short link belongs to a QR service, which forwards each scan to wherever you've pointed it today. You can change the destination after printing, and the service can count the scans. The catch is that the code depends on that service staying up and your account staying active. Our page on dynamic QR codes explains how they work, and dynamic vs static QR codes compares the two side by side.
Whether either kind expires is its own question, answered in do QR codes expire?
What does QR stand for? Quick response. DENSO WAVE named it for how fast it reads.
Who invented the QR code? A team at DENSO WAVE in Japan led by Masahiro Hara. It was announced in 1994.
Are QR codes free to use? Yes. DENSO WAVE says no application or license is needed, as long as you follow the JIS or ISO standard. Making one with a generator is free too; a dynamic code that you can edit usually costs something, or comes with limits on a free plan.
Is "QR code" a trademark? The word "QR Code" is a registered trademark of DENSO WAVE in Japan and other countries. The pattern itself is not.
Can a QR code contain a virus? A QR code holds text, usually a link. It can't run anything by itself. The risk is the page the link opens, so read the address your phone shows before you tap it.
Free static codes, no sign-up. For a code you can change after printing, QRZY's Free plan gives one editable code with a 5-second countdown on every scan.
QR Code is registered trademark of DENSO WAVE INCORPORATED.
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