QR Code Basics - How They Work, How to Scan Them, and How to Make Your Own

You've probably used a QR code to pay at a store or scanned one on a poster with your phone. QR codes pop up everywhere in daily life, but do you know what's actually inside those black-and-white squares? This article explains QR code basics from the ground up in a friendly, easy-to-follow way.

The barcodes on products at the supermarket store information using the thickness of horizontal lines. They can hold about 20 digits of numbers at most. That's enough for a product ID, but nowhere near enough for something like a URL.

QR codes, on the other hand, store information in two directions - both horizontally and vertically. "QR" stands for Quick Response, and they were invented in 1994 by Denso Wave, a Japanese auto parts manufacturer. They were originally designed for tracking parts in factories, but they spread worldwide because of how useful they are. Since information is packed in two dimensions, QR codes can hold up to 7,089 digits of numbers or 4,296 alphanumeric characters. That's a massive leap from barcodes.

QR codes also have an "error correction" feature. Even if part of the code gets dirty or damaged, the remaining parts can reconstruct the original information. That's why you can often scan a QR code even if the poster is slightly torn. This feature also makes it possible to place a logo in the center of a QR code without breaking it.

The content of a QR code is entirely up to the person who creates it. Here are the most common types of information stored in them.

The most popular use is URLs. By turning a website address into a QR code, anyone can open the page just by scanning it with their phone. No need to type out a long URL on a keyboard, which makes QR codes a perfect match for posters and flyers.

You can also store plain text. For example, turning a Wi-Fi password into a QR code lets guests connect just by scanning it. You'll see this a lot at cafes and hotels.

Contact information (vCard) can be stored too, turning a QR code into a digital business card. When someone scans it, their name, phone number, and email address get automatically added to the phone's contacts. It's like a modern version of exchanging business cards.

Beyond that, you can encode email addresses, phone numbers, map coordinates, and all sorts of other information into QR codes.

Most modern smartphones can scan QR codes without installing any special app. On an iPhone, just point the default Camera app at a QR code and a link will appear at the top of the screen. Most Android phones can scan directly from the camera app too. If it doesn't work, try using the Google Lens feature.

The trick to scanning is making sure the entire QR code fits within the camera frame. Scanning at an angle works to some extent, but pointing straight at it is faster. In dark places, turning on your phone's flashlight helps. If you're scanning a QR code displayed on a screen, crank the screen brightness up to max for the smoothest experience.

You can create QR codes for free and it's super easy. Search for "QR code generator" in your browser and you'll find tons of free tools. Just enter a URL or text, hit the "Generate" button, and you're done.

The QR code you create can be downloaded as an image file (PNG or SVG), so you can paste it into posters or presentation slides. If you're printing it, make it at least 2cm x 2cm so it's easy to scan.

If you put a really long URL directly into a QR code, the black-and-white pattern becomes so dense that it can be hard to scan. The longer the URL, the more data needs to be stored, which increases the QR code's complexity.

This is where short URLs come in handy. Shorten the URL first, then turn it into a QR code - the pattern stays simple and scannable even when printed small. On top of that, many URL shortening services offer click analytics, so you can track how many times your QR code was scanned. Being able to measure the effectiveness of an event flyer in actual numbers is a huge advantage.

Putting a QR code on a school festival poster lets you direct visitors to your class's info page or social media account. For example, create a web page with your booth's menu, shorten the URL, and turn it into a QR code. Anyone who sees the poster can scan it and check the menu right on their phone. You could also put QR codes on signs around the school that link to the day's schedule or a map of classrooms. It's easier than printing a mountain of paper pamphlets, and you can update the content in real time.

QR codes are the next evolution of barcodes - a Japanese invention that packs URLs, text, contact info, and more into a tiny square. They're easy to scan with your phone's camera and free to create. Combine them with short URLs for better scannability and built-in analytics. Next time you're making a poster or flyer, give it a try.