What Are QR Codes and How Do They Work?

You’ve probably seen QR codes. They’re everywhere, from websites to advertisements. They look a bit like barcodes but, instead of vertical stripes, they are made up of square–shaped patterns. As an increasing number of businesses start to use them, they are becoming more and more recognizable, and many smartphones now come with built-in QR readers.

A QR code linking to

But what exactly are these so–called QR codes, and how do they work? Here's everything you need to know.

What Does QR Stand For?

QR stands for "Quick Response."

While they may look simple, QR codes are capable of storing lots of data. But no matter how much they contain, when scanned, the QR code should allow the user to access information instantly – hence why it’s called a Quick Response code.

A Brief History of The QR Code

The first QR code system was invented in 1994 by Japanese company Denso Wave, a Toyota subsidiary. They needed a way to track vehicles and parts during manufacturing more accurately. To achieve this, they looked to develop a type of barcode that could encode kanji, kana, and alphanumeric characters.

Going beyond the barcode

Standard barcodes can only be read in one direction – top to bottom. That means they can only store a small amount of information, usually in an alphanumeric format.

But a QR code is read in two directions (hence why it is sometimes also referred to as “two–dimensional barcode") – top to bottom and right to left. This allows it to house significantly more data.

The development team behind the QR code wanted to make the code easy to scan so that operatives didn’t waste time getting it at the right angle. They wanted it to have a distinctive design to make it easy to identify. This led them to choose the iconic square shape that is still used today.

The first QR code took over a year to develop. It could hold up to 7,000 numerals plus kanji characters, and it could be read ten times faster than a standard barcode.

The QR code becomes open source

Once released, the QR code was quickly adopted by the auto industry. This was especially important at the time, as many consumers in Japan were demanding more transparency from large corporations. They wanted to know exactly where their products had come from – and not just cars but also food, pharmaceuticals, and other products. The QR code was, therefore, gradually integrated across the manufacturing industry.

Denso Wave was kind enough to make their QR code publicly available — while declaring they would not exercise their patent rights. This meant anyone could make and use QR codes (even to this day).

However, the initial uptake of the idea was slow, and while QR codes themselves were easy to produce, QR readers were not generally available to the public. That was until…

2002: the first mobile QR readers

In 2002, the first mobile phones containing built-in QR readers were marketed in Japan. This led to an increase in the number of companies using QR codes, and the first consumer ready QR codes started to appear.

Meanwhile, the technology continued to evolve. In 2004, a micro QR code was created, and, in 2008, the iQR code – which had rectangular modules – was released.

Also, around this time, the first iPhone hit the market, which put QR readers into the hands of a greater number of consumers worldwide. Realizing the potential of QR codes for sales and marketing, brands and organizations started to create their own.

The golden age of QR codes

In 2012, eighteen years after its inception, the QR code was awarded a Good Design Award for industrial design.

At this time, the QR code had spread around the world — it could be seen everywhere from billboards, magazines, leaflets, and other places.

Even today, in 2020, Denso Wave continue to improve on their original design. Their new QR codes have integrated solutions such as traceability, brand protection, and anti-forgery measures. There are also many new uses for the QR code, from transferring payments to determining objects' positions within augmented reality.

How Do QR Codes Work?

The patterns within QR codes represent binary codes that can be interpreted to reveal the code's data.

A QR reader can identify a standard QR code based on the three large squares outside of the QR code. Once it has identified these three shapes, it knows that everything contained inside the square is a QR code.

The QR reader then analyzes the QR code by breaking the whole thing down to a grid. It looks at the individual grid squares and assigns each one a value based on whether it is black or white. It then groups grid squares together to create larger patterns.

QR code on mobile

What Are The Parts Of A QR Code?

A standard QR code is identifiable based on six components:

Quiet zone

This is the empty white border around the outside of a QR code. Without this border, a QR reader will not be able to determine what is and what is not contained within the QR code (due to interference from outside elements).

Finder pattern

QR codes usually contain three black squares in the bottom left, top left, and top right corners. These squares tell a QR reader that it is looking at a QR code and where the outside boundaries of the code lie.

Alignment pattern

This is another smaller square contained somewhere near the bottom right corner. It ensures that the QR code can be read, even if it's skewed or at an angle.

Timing pattern

This is an L-shaped line that runs between the three squares in the finder pattern. The timing pattern helps the reader identify individual squares within the whole code and also makes it possible for a damaged QR code to still be read.

Version information

This is a small field of information contained near the top–right finder pattern cell. This identifies which version of the QR code is being read (see “What are the four versions of the QR code?”).

Data cells

The rest of the QR code communicates the actual information, i.e., the URL, phone number, or message it contains.

What Are The Four Versions Of The QR Code?

QR codes can be used for lots of different purposes, but there are four widely accepted ‘types’ of QR code. The version used determines how data can be stored and is called the “input mode." It can be either numeric, alphanumeric, binary, or kanji. The type of mode is communicated via the version information field in the QR code.

Numeric mode

This is for decimal digits 0 through 9. This is the most effective storage mode, with up to 7,089 characters available.

Alphanumeric mode

This is for decimal digitals 0 through 9, plus uppercase letters A through to Z, and the symbols $, %, *, +, –, ., /, and : as well as a space. It allows up to 4,296 characters to be stored.

Byte mode

This is for characters from the ISO–8859–1 character set. It allows 2,953 characters to be stored.

Kanji mode

This is for double–byte characters from the Shift JIS character set and is used for encoding characters in Japanese. This is the original mode, first developed by Denso Wave. However, it has since become the least effective, with only 1,817 characters available for storage.

There is also a second kanji mode called Extended Channel Interpretation (ECI)mode that specifies the kanji character set UTF–8. However, some newer QR code readers will not be able to read this character set.

There are two additional modes which are modifications of the other types:

Structured Append mode

This encodes data across multiple QR codes, allowing up to 16 QR codes to be read simultaneously.

FNC1 mode

This allows a QR code to function as a GS1 barcode.

Can A QR Code Use Multiple Modes?

It is possible, so long as each QR code contains the correct version information field.

paying with QR codes

What Are The Advantages Of QR Codes?

The QR code was designed to improve upon the design of a barcode.

It can contain more information than a barcode.

A barcode can only contain a single string of information in the form of a numeric code. This makes it useful in retail environments, as it can quickly and accurately identify a product that has a unique number attached to it. However, it can't do much more than that.

Meanwhile, a QR code can contain much more information and in many different types (such as words and characters). It does this all within roughly the same space as a barcode, and it is just as easy to generate and print.

Fewer errors

Have you ever taken an item to the checkout and scanned the barcode, only for the machine to come up with a completely wrong item? This is a rare circumstance, but it usually happens because a barcode is not protected against duplication. QR codes are designed to minimize this from happening as they have the capacity to store more information (which allows for more fail-safes to be built in).

Easy to read

Unlike barcodes, which require special technology to read and interpret, QR codes can be read and understood by smartphones and digital cameras. This makes them much more useful for things such as consumer-facing marketing campaigns.

Easy to print

Like a barcode, a QR code requires only black and white printing (although any color or even multiple colors can be used).

More secure

It is possible to encrypt the information in QR codes, offering an extra level of protection.

What Are the Different Types Of QR Code?

It is possible to create QR codes in many different shapes and styles, but there are five types that are most commonly found. They all do the same job – they just look slightly different.

QR code

This is the original version of the QR code created by Denso Wave in the 1990s. It's easy to identify by its three finder patterns in the bottom–left, top–left, and top–right corners.

Aztec code

While it looks similar to a QR code, the Aztec code, developed by Welch Allyn, contains only one finder pattern, right in the middle.

An Aztec code linking to


This type of QR code is used by the United States postal service. It’s similar to the Aztec code, in that it places the finder pattern in the middle, but it uses a honeycomb pattern instead of squares.

A Maxicode linking to


Invented in 1991 by Ynjiun Wang of Symbol Technologies, the oddly named PDF417 predates the QR code by three years. It looks like a mix between a QR code and a barcode and is easily recognizable by its rectangular shape.

A PDF417 linking to


Developed by a software company of the same name, the Semacode is a data matrix that looks a lot like an ordinary QR code but doesn’t have recognizable finder patterns.

A Semacode linking to

How Do I Scan A QR Code On My iPhone, iPad Or Android Device?

Most smartphones have built-in QR scanners. Some of the most recent smartphones to hit the market, such as the newest Google Pixel phone and iPhones, have QR scanners built into their cameras.

how to use QR codes

Even some tablets, such as the Apple iPad, have QR readers built into their cameras.

Some older devices may require a particular app to read QR codes, but you'll find no shortage of these apps available on the Apple App Store and Google Play.

Scanning a QR code using your device couldn’t be easier:

  1. Open the QR reader application or the camera on your smartphone.
  2. Point it at the QR code – you should be able to point your camera from any angle and still receive the necessary information.
  3. The data will be instantly shown on screen – for instance, if the QR code contains contact details, these should be instantly downloaded to your phone.

What Information Can QR Codes Contain?

Like a barcode, a QR code stores data. This data can include website URLs, phone numbers, or up to 4,000 characters of text.

QR codes can also be used to:

  • Link directly to download an app on the Apple App Store or Google Play
  • Authenticate online accounts and verify log-in details
  • Access Wi-Fi by storing encryption details such as SSID, password and encryption type
  • Send and receive payment information.
  • Much more – a company in the UK called QR Memories even creates QR codes for use on gravestones. Allowing people to scan the code to read more about that deceased persons life (if they have an obituary or news story relating to them online).

Where Are QR Codes Found?

QR codes were initially invented to help track parts in vehicle manufacturing, and they are still used throughout the manufacturing industry.

You'll also find QR codes utilized by other businesses that need to keep a close eye on products and supplies, such as the construction, engineering, and retail industries.

Postal services around the world also use them. Because they contain a large amount of information, such as postal addresses, they are becoming increasingly relied on to track parcels.

QR codes are now also used at colleges to help engage with students. They’ve appeared everywhere from the classroom to the library, where they are used to help students find the books they’re searching for.

Examples of QR code use in marketing and advertising campaigns

The places you are more likely to see QR codes in your day-to-day life are in sales and marketing campaigns.

Many advertisers like to use QR codes in their campaigns because it provides a faster and more intuitive way to direct people to websites than by entering URLs manually.

They can even be used to link directly to product pages online. For instance, if you were searching for the exact dress a model was wearing in a poster, a QR code could directly take you to the web page where you could purchase it.

You may also find QR codes on the packaging for some of your favorite products. These QR codes can reveal information about the product, such as nutritional information, or special offers you can use for next time.

QR code use and definition

You can put a QR code just about anywhere. So, don't be surprised if you start to see them appearing everywhere, from business cards to signposts and even receipts.

How Do You Create A QR Code?

Creating a QR code is much easier than you might think.

There are dozens of QR code generators available to download for your smartphone via the Apple App Store and Google Play.

You can also generate them online using several websites, such as:

The benefits of using a QR code generator are that you can quickly generate a QR code based on the information you enter (whether it's a URL, a contact card, a calendar event, or text). You can even customize the design with different colors and instantly download and share the image file.

Once you have the design of your QR code, you can recreate it using different media. So long as the QR code's shape can be read and understood by a smartphone, you can make a QR code out of almost anything.

Creative ways to create QR codes

In Zhengzhou, China, more than 2,500 students from Sias International College came together in 2017 to form the world’s largest human QR code. The students held up umbrellas to create the pattern, which measured 51 meters across. When scanned, students received a special offer from rideshare company Didi–Express.

Also, in China, in the village of Xilinshui, over 130,000 juniper trees were planted across 12 acres in the shape of a QR code, which could be viewed from above. When scanned, it directed users to view Xilinshui’s official tourism page.

Many companies have come up with other creative places to create QR codes. Here are some of the more imaginative ways we’ve seen people use QR codes:

  • As a rubber stamp
  • On t–shirts
  • On Christmas gift tags

QR code – FAQs

Do QR codes have to be in black and white?

No, they can be any color, so long as the contrast between light and dark areas is clear. QR codes can even be multicolored.

Do many people use QR codes?

Data suggests that QR code usage is on the rise. According to Scanova and Statista, an estimated 11 million households will scan a QR code in 2020 – this is a significant increase from the estimated 9.76 million scans in 2018.

This is because of three main reasons: smartphone penetration has increased from 10% in 2014 to 36% in 2018, while high-speed mobile internet grew from 48% in 2014 to 61% in 2018. Also, many new smartphones now have QR scanners built-in, giving more people the ability to scan QR codes when they’re out and about.

Are QR codes safe?

Because QR codes contain a lot of data, it’s possible to hide phishing information within them. Savvy hackers could also use QR codes to direct users to disguised malware downloads or force the user’s mobile phone to send premium text messages.

And in the case of QR codes that point to URLs, there is the potential that the domain they direct users to — could be hacked. In one famous example, a German condiments company (who shall remain unnamed) accidentally led users who scanned their QR code to an adult website.

How to Protect Yourself from Malicious QR Codes

There’s no telling where and when you might come across an infected QR code. That’s why it’s essential to choose a QR Scanner you know you can trust.

Kaspersky QR Scanner instantly checks that a scanned link is safe before submitting any information to you.

That way you know if dangers lie behind a QR code, such as:

  • A phishing scam
  • A forced app download or premium text message scam
  • Dangerous links

Kaspersky QR Scanner still provides everything you need from a QR Scanner, such as adding contacts to your phone. But it also creates a log of past scans so you can trace back to see when and where you may have been compromised.

Related links:

What is QR Code? Is it safe to scan QR codes

What is a QR code and how do they work? We take you through everything you need to know about these enigmatic and innovative barcodes.
Kaspersky Logo